These are what we call the 'YMMV items.' Things that some people find in this work. We call them 'your mileage might vary' because not everyone sees these things in the same way. This starts discussions in the trope lists, a thing we don't want. Please use the discussion page if you'd like to discuss any of these items.
The Tau. Sinister fundamentalist collectivists with no place for individuality, or idealistic and good-hearted folk heroically seeking a prosperous future for the universe? Alternatively, a hopelessly naive species doomed to sink in the mire of GRIMDARK reality, or bearers of the hopeful torch the universe needs to rekindle itself?
The Craftworld Eldar: Utterly amoral self-serving bastards, or tragic atoners who just want to save their dying people from extinction? Villains, or victims? Reluctant distant allies of humanity against the encroaching void, or among mankind's most insidious foes?
Author's Saving Throw: Invoked by Games Workshop policy. Virtually every story is in-universe propaganda, so anything that turns out too unpopular can be safely "clarified". The Grey Knights provide a nice example in 2014: Kaldor Draigo's write-up in the Grey Knights codex described him as beating down Mortarion and carving Supreme Grand Master Geronitan's name into his heart. Fans were not impressed at the Mary Sue display. The audio drama Mortarion's Heart greatly expands on and provides context for how that happened. The latest Grey Knights Codex dropped the reference entirely.
The Emperor understandably underwent this after he went on life support. Compare how he looks before◊ and after◊ the Horus Heresy. Interestingly, though, it's implied he's still kicking the crap out of the Warp-forces from within their domain.
The Necrons in general, and the Void Dragon in particular, have been steadily losing their mystery and power since being introduced, possibly due to their lack of a recent codex and their original overpowered status. Though in Sandy Mitchell's Ciaphas Cain(HERO OF THE IMPERIUM) books, the Necrons are still virtually unstoppable nightmares and the only thing that Cain absolutely will not fight unless there's no alternative. Their fifth edition codex turned them into bitter individuals who want to become flesh again and merely want to reconquer their empire when they're not busy infighting, instead of unstoppable Omnicidal Maniacs who will stop at NOTHING for destroying every living things in the galaxy. It is also emphasized a lot more than before that they suffered many losses during their long sleep. Whether or not this new direction was a good thing is a hugeBase Breaker.
The Tyranids' 6th Edition codex has removed a good number of their deployment options and a good number of their most powerful units, including the Doom of Malan'tai (although to be fair, Malan'tai in a spore pod was fairly cheesy). They've been significantly nerfed, and were a low tier army before the update, knocking them down to bottom tier along with the Sisters of Battle. So much for the "Great Devourer".
Either Squats were incredibly stupid and Games Workshop did the right thing by retconning them away, or they were incredibly awesome and should continue to be supported. There are no in-betweens.
Rogue Trader (the original, not the tabletop RPG) was either stupid and GW's current direction is magnificent or it was completely crazy awesome and should be brought back.
The Ultramarines, the Grey Knights, and the Tau due to their alleged "Mary Sue" status.
The Necrons' new direction after their 5th Edition 'dex was hugely controversial. Prior to 5th Edition, the Necrons were a race of soulless automatons, deceived and enslaved by the C'tan, a race of ancient star gods who hungered for souls. The new Necrons are The Remnant of an ancient Empire, who shattered the C'tan after the C'tan deceived them and who now form their own royal courts and their own factions. Fans of the old fluff claim that the "Newcrons" have destroyed the old, Cthulhu-style mystique. Fans of the "Newcrons" argue that the old Necrons were excessively characterless and that the updated fluff makes the race more interesting but keeps them as terrifying abominations.
While one of the most well known factions in the setting, the Eldar are this to some circles of the fanbase due their sheer arrogance, being almost exactly like the Imperium and yet still look down everyone else.
The Space Wolves.
Some love them for being drunken, wild-partying anti-authority space vikings. Some hate them for that exact same reason. Their sheer diversity of character in the fluff has also garnered criticism. The fluff has portrayed them with themes as varying as grim and brooding executioners, party bros, honorable marines out for the little guy, psycho-indoctrinated super soldiers, military geniuses, combat pranksters, vicious werewolf berserkers, and disciplined combined-arms soldiers. A lot of the hate also comes from people who dislike the hypocrisy and brutality with which they handled the Thousand Sons at Prospero, especially because they also use psykers in the form of Rune Priest. Finally, it must be said, that a lot of the hate comes from their extremely powerful (When it came out) codex, that was essentially just Marines, only cheaper and better.
The Space Wolves are interesting in that even fans of the chapter have a Broken Base; which portrayal of the chapter is best? Some prefer the honorable bro-marines, some the grim berserkers of the 31st Millennium, some choose a depiction in between.
Even Space Wolf models are developing a Broken Base, as many people are wondering if the wolfy wolf wolves on everything (like this;◊ a rocket sled pulled by giant wolves) is Crazy Awesome or just ridiculous.
What is the better name? "The Imperial Guard", or "The Astra Militarum"? For that matter, the Militarium Tempestus; it either brought back the old Inquisitorial Stormtroopers people wanted and brought in some awesome formations for use by all imperial armies, or it was a cheap cashgrab on GW's part by making an army that cost less in point, but more in money than space marines, especially since the codex lacks even the basic "relics" section, which even other supplements have.
Recent Horus Heresy books have brought back Ollanius Pius (aka the epitome of a Badass Normal), the Guardsman who stood up to Horus on the latter's battle barge in a doomed Last Stand after Horus had just defeated the Emperor, but have made him a Perpetual, a 30,000 year old being with Resurrective Immortality. People feel rather strongly about whether or not this was a positive change.
Complacent Gaming Syndrome: Lots. The largest case is with armies, since players will typically go for whatever army is updated the most recently since as an edition goes on, the creators start figure on what makes an army effective under the current rules, so the more recently updated armies tend to be better than the ones released earlier. Also, the cost of models means that Space Marines get the most use this they're, relatively speaking, the least expensive to play. Games Workshop has noticed this focused very heavily on releasing more and more Space Marine armies.
Ezekyle Abaddon, known as The Despoiler, is the heir of the fallen Primarch Horus. Abaddon is consumed with hatred for all that lives, even his former master, and seeks nothing less than the extermination of all he can manage while uniting humanity under the dark banners of Chaos. As the only man with the support of all the Gods of Chaos, Abaddon has united the forces of Chaos under his banner no less than thirteen times in the Black Crusades. During these ventures, Abaddon storms the galaxy itself, burning and destroying all he can until the forces of the Imperium inevitably defeat him. Abaddon hardly minds as he is able to destroy and kill in great number, something he loves more than anything else. Willing to send countless numbers of his own to their doom and living only to destroy everything he can, Abaddon is the champion of Chaos and is one of the most evil and brutal beings in all of the dark world of Warhammer 40,000.
Fabius Bile is what you have when you cross a Mad Scientist with the dark powers of Chaos. Bile traverses the Galaxy more than any other member of the Traitor Legions for the purpose of experimenting whenever and wherever he can. On the world of Dimmamar, Bile changed the atomic composition of the air until the population was forced to ingest his transformative serums or slowly suffocate. He earned the name "Manflayer" in the Bray system for skinning those who opposed him to make a cloak of human skin, the survivors still alive to carry the garment behind him. Bile injects poisonous strands into every gene pool he can, with some experiments wiping out life in entire sectors. A sadist with a god complex and scientific curiosity, Bile is feared and hated by all who know his name and actions.
Crack Pairing: Nurgle and Isha. Interestingly, this is technically canon, though unreciprocated.
The Ork race. Practically everything that's ever been accomplished by Orks has happened merely because the things in question are Crazy Enough to Work. Possessing psychic powers that turn their asinine and downright insane thoughts into reality helps, too.
The Space Wolves chapter. Boisterous Bruisers who throw out the Codex Astartes and tell the High Lords of Terra to piss off, these people should have been declared traitors millennia ago, yet they get away with everything.
Whilst opinions of the Chapter as a whole and Guilliman in particular are mixed, most people agree that this◊ image is definitely crazy awesome. He's punching a Marine's head off. In space. Without a helmet. Bad. Fething. Ass.
The Prioris variant of the Sisters of Battle's Exorcist armored fighting vehicle. It is, for all intents and purposes, a rocket artillery launcher shaped like a giant organ, with the organ's keyboard as the firing mechanism. The model is noted as the only time Citadel Miniatures actually managed to out-do Forge World in terms of design, as Forge World usually puts out fantastic high-end models but only produced a more conventional Multiple-Rocket Pod Exorcist.
Creator's Pet: The Ultramarines are the Jack of All Stats of the Space Marines, being a good and noble chapter with no glaring strengths or weaknesses. Authors largely agree that they should have a flaw to balance that out (such as pride, dogmatism, or arrogance), but they have difficulty agreeing on which. Matt Ward, however, does not agree that they should have a flaw. As he will happily explain at great lengths, they are the best Space Marines, and their Primarch is the Spiritual Liege of all other chapters. Fluff written by him tends to focus on the Ultramarines disproportionately, with other Space Marine factions in awe of their skill and abilities. Any individuals who dislike them are quickly proven wrong and/or evil.
Creepy Awesome: A major draw of the franchise. Specific examples include the following:
The Noise Marines, who embody The Power of Rock turned to Chaos! "the years of bloody warfare have honed their bodies into sensory extremes where nothing can stir their emotions other than the din of battle and screams of the dying".
The Necrons pre-6th Edition and/or the Necrons post-6th Edition. The base is divided on whether they were this before, after, or both.
The entire core of Da Orks' humor is their ridiculously, overwhelmingly violent nature.
The Imperial Guard/Astra Militarium also gets in on the fun. One Commander Chenkov once ordered an entire squad of his troops executed because he ran out of mortar for the walls. And then there are the Catachans, who consider surviving to age 10 an achievement on their Death World.
Darkness-Induced Audience Apathy: Almost all of the story beyond the actual tabletop sessions (since you model and customize your personal army, letting you make them exactly as dark or noble as you like) and the codex books (which are highlights of victories and propaganda). There are so many Shoot the Shaggy Dog stories, and unequivocal victories for any given side are happening at the same time as a dozen crushing defeats.
The Emperor tends to be painted by fans as the one purely good character in the whole setting. While he was probably better than the current management, he did have his fair share of atrocities under his belt.
Speaking of Khârn's god, Khorne himself may rival the Emperor in terms of Draconess. According to Games Workshop, he is the god of bloodshed and hate, who cares not from where the blood flows, only that it flows, be it bystanders or his own worshipers. According to a good portion of the fanbase, Khorne is the god of Proud Warrior Race Guys and martial honor who wouldn't lay a hand on innocent civilians. This version is actually based on older editions, but the merciful aspect is clearly out of date as far as Games Workshop is concerned. It helps that his fantasy version is essentially "Evil Odin".
Imperial Guard Commissars get a surprising amount of this as well, due to the influences of Ciaphas Cain and Gaunt's Ghosts. Chances are pretty damn good that your average Commissar does not want to be buddy-buddy with the men.
Happens a lot with the Eldar and Tau, as well. Quite a few people view the Eldar a bit too sympathetically, and gloss over their numerous atrocities, not to mention that a good portion of the galaxy's woes can be blamed solely on them. As for the Tau, well, some people really do consider it a rather pleasant place to live, nevermind that it's got a very British Empire-esque policy on natives; if you're a human or Kroot, you won't be exterminated, and you won't exactly be a slave, but you'll still get quite a rough deal from people who look down on you.
Followers of Chaos can start as this. Many of the Chaos Space Marines fell not out of evil, but simply bad circumstances. Human followers who have fallen since then have arguably good reason, given that life in the Imperium is so bad joining cults is a legitimate alternative to alleviate their misery. All in all, mortal followers of Chaos aren't evil, they're just insane. Daemons, on the other hand...
The Imperium is very intolerant of "traitors" who have turned to the Tau's offer of egalitarianism, though readers might think differently. Despite the Tau being space-Trotskyists at best and Stalinist imperialists at worst (not to mention the sincerity of their offers of brotherhood), many consider them better than the "Catholic Space Nazis" of the Imperium.
The Adeptus Mechanicus, to a certain degree among the fanbase.
The Imperial Fists (and related Space Marines chapters) qualify. They have a much larger fanbase than the limited amount of fluff and overly generic nature should indicate. If they win, it is usually as part of a battle force consisting of multiple Space Marine chapters. If they are by themselves, they tend to lose more often that not. The defining characteristics are an increased emphasis on will power, pain being educational, and discipline. These are all defining characteristics of every single Space Marine anyways. They aren't one of the "never had anyone fall to Chaos" chapters, so they clearly do not have a will-power advantage in actual practice. Space Marines are already some of the most highly disciplined troops in the setting. Pain being educational is kind of meh when you consider most Space Marine candidates die during training. They don't lose enough to be The Woobie, they don't win enough to be Badass, and they are defined by being uniquely more generic than most Space Marine chapters. On the other hand they are excellent fighters of siege warfare, they were the only legion who were allowed to recruit from Terra, and they were one of the most important legions to the defense of Terra from Horus. Despite being Out of Focus they are the second most important chapter in the entire Imperium.
Amongst the Imperial Guard, the Commissars, despite them in the game just being a unit that gives a small buff to statline and leadership, has a huge following to the point where it's almost mandatory for Imperial Guard novels to include at least one.
Khârn the Betrayer is the most popular named Chaos Space Marine character due to his unfailing ability to kill everything around him, his role as the protagonist of the excellent short story The Wrath of Khârn, and his starring in a series of comedic fanfics on 4chan that portray him as a pretty nice guy despite the Ax-Crazy. Thanks to his popularity, Khârn is set to have a book detailing one of his adventures.
For the first time ever since Matt Ward's relentless shilling reduced them to Scrappy status, some Ultramarine characters are this. Specifically, these characters are found in the Horus Heresy novels such as the Tetrarchs, whose main quality seems to be comically over-sized shields and badassery.
The Iron Warriors, despite not being the most prominent of the Chaos Legions, have a following for being much less Stupid Evil than the rest.
The daemon prince Doombreed has a surprisingly following for a character that's only referenced in the background.
Tzeentch is probably the most popular of the Chaos Gods next to Khorne, despite receiving the least focus.
The Space Wolves standing against much of the Imperium's Kick the Dog against its own people helped earn them a sizeable following, prior to their 5th edition Codex where they were turned into a Tier-Induced Scrappy because of how they were in a number of ways a better version of the vanilla marine codex. The Salamanders as well, for similar reasons; although they're relatively small-time compared to the other chapters, they have a very large fandom because they're pretty much the only Space Marines who will go out of their way to help and protect regular people. Shooting civilians is something they... frown upon.
There's a lot of people in the community who would like to see a codex for the Rak'gol, a relatively minor xenos race. Think the Reavers, except they're cyborg scorpion creatures... and they're evenworse.
Gateway Series: For many people, this introduced them to tabletop wargames.
Genius Bonus: There's little references tucked away everywhere, ranging from sci-fi to military history to history in general to Scandinavian and Ancient Babylonian myth.
One of the first worlds in the path of the first Tyranid Hive Fleet was named "Prandium", which is Latin for "lunch."
One of the symbols of the Imperium is a double-headed eagle. In and of itself, this is not surprising, as some of the most powerful and influential empires on Earth (the Byzantines, the Russians, the Holy Roman Empire) have used the same symbol, and it would be just like the Imperium to adopt such a symbol of absolute autocracy. The real bonus comes into play if you consider the God-Emperor's origins; according to one sourcenote whose current canonicity is disputed, he was born in Anatolia (modern Turkey), where double eagle symbolism has been particularly strong for thousands of years. Also, the Imperial Eagle in some depictions looks very like the Nazi variant of the Reichsadler.
In Western magical traditions, the number 3 has a great deal of occult/magical potency. Tzeentch's sacred number is 9, being three squared (three times three, or three plus three plus three) and the only number more inherently powerful than three. Perfect symbology for a god of magic.
The Adeptus Mechanicus's belief in that all technology already exists in the galaxy and only needs to be discovered seems like it's illustrating just how backwards they actually are, but if you talk to any decent programmer, they can basically sum up programming as "discovering the path to the program you want". As all programs are made from mathematical symbols put into sequences, it literally means all programs exist right now, you just need to input the correct sequence to access it (which is one method of thinking when it comes to actually writing scripts and programs). Hence, all technology does really exist, it just depends on your definition of "discovery" and "creation". Considering the Adeptus Mechanicus are often shown to merge themselves with technology, this would be a logical assumption (if somewhat skewed) on their part.
The aforementioned Rainbow Warriors name being a double reference. One to the Greenpeace vessel, the other to the Native American legend.
The game is much more popular in the United States than in its native Britain, with most of the spin-off video games being developed by American and Canadian companies. Of course, the United States having a population five times larger than the United Kingdom (thus equaling a larger potential fanbase) might contribute to this. Another major factor is that in Britain it's generally considered a children's game for rich kids, while in the US it's associated with college students and other adults (i.e. people with their own money).
Americans Love The Tau: The Tau are one of the most commonly collected armies in the US, while they have middling popularity at best in Britain and Europe. It might have something to do with the sleek, Robotech-esque aesthetics of their technology, particularly their Humongous Mecha.
Germans Love 40k As Well: Next to Dungeons & Dragons - of course - Warhammer 40,000 ranks as one of the most popular Tabletop Games known in Germany. This may have to do with the considerably German middle ages-styled Imperium, the imagery and the tanks of the Astra Militarum.
During the late 90s/early 2000s, a series of fluff articles about the various Space Marine chapters and Traitor legions was run in White Dwarf magazine. The Word Bearers article claimed it was unique amonst the Traitor Legions in that its Chaplains were also corrupted, instead of being slain for their defiance in the face of heresy. Come the Horus Heresy novels, and it turns out that the Word Bearers have "Traitor Chaplains" because they were the only Legion to have Chaplains prior to the Heresy — and these Chaplains were actually instrumental in corrupting them in the first place.
Furthermore, Lorgar's goals prior to turning to Chaos was to officially promote the Emperor's divinity and turn the Imperium into a theocracy united under the God Emperor, even going so far as to try and encourage his fellow Legions to adopt Chaplains. In other words, Lorgar has actually won, despite his descent to Chaos.
Artwork of Cat Girls is nothing new, even when it's 40k related. Come 6th edition and the rule book actually mentions entire regiments made out of cat people.
HSQ: Not just swords, chainswords! Not just Space Marines, ten-foot tall genetically-enhanced superhumans in huge Power Armor tearing up hordes of enemies, hard-dropping from orbit like meteorites! Not just a Red Shirt Army, but billions of troops throwing themselves into the maw of death FOR THE EMPEROR! Not just Mordor, but a twisted evil area of space hundreds of light years across! Not just the Inquisition of a repressive religious theocracy, but one that can destroy worlds for the taint of heresy! (And worse, it might be the most practical decision!) You must have thought of a few expletives when you saw the pages, at least.
Poor, poor Eldar. Not only are you the whipping boys of the entire game, most of your race got Mind Raped by an Eldritch Abomination and if you're not careful enough, you'll get tortured and raped by Horny Devils for all of eternity. That sure justifies being Manipulative Bastards who would let billions of other races die horrible agonizing deaths to save a few of your own.
The 5th Edition fluff makes the Necrons out to be this—on one hand, they're responsible for their own current, miserable state of being, and they're feared by all other races for a good reason. On the other, they still don't deserve being forced into it, and the majority of Tomb Worlds wish nothing more than to be left alone.
The most effective Dark Eldar (those who aren't obnoxious Smug Snakes) fall into this category, especially Asdrubael Vect, who engineered a coup that elevated him from a slave to a gang leader to the High Lord of Commorragh.
Tzeentch is the god of Magnificent Bastards. On the mostly-mortal side of things, the Alpha Legion of Chaos Space Marines is composed of Magnificent Bastards.
The Laughing God of the Harlequins is the other "good" example (but still a total asshole, so not a Guile Hero).
Szarekh, the Silent King of the Necrons. Sure, he was duped into trading away their souls... so he killed their Gods.
Trazyn the Infinite, to the extent that 1d4chan have added TRAAAAAAAAAAAAAAAAZYN! to their lexicon.
The Ultramarine domain of Ultramar: a functional, prosperous, stable realm in the otherwise decaying Imperium. It still isn't a very nice place to live, though, given that, as one of the hardest realms of the Imperium, every up-and-coming alien warlord, Chaos daemon prince, Tyranid Hive Fleet, or Tau Shas'O wants a go.
Subverted by the Tau Empire, whose propaganda tries to put out that they are this. And people still consider them to be a Mary Suetopia compared to the general grimdarkness of the setting.
Tzeentch, although it's justified since he is after all the god of scheming.
The Emperor and the Primarchs. Somewhat justified, as the Emperor had 40,000 years to refine military tactics, while the Primarchs were designed to be that.
Commander Shadowsun of the Tau Empire. Led a Tau armada against a Tyranid splinter fleet and wiped it out without losing a single ship. Made more impressive by the fact that she's a Fire caste commander, so she had no experience in space combat. Sweet Jesus.
Imhotek's profile lists him as a having an ability to predict a battle the descends into Gambit Roulette territory with how he's supposedly able to predict every single move, feint, counter feint, advance, and any other move an army either side can make with such an implausible ability that borders on omniscience.
A wiki called 1d4chan (based off 4chan) has turned Eldrad Ulthran into a dick, er, prescient jackass, who will form complicated schemes just so a commissar's hat gets blown off and lands right on Eldrad's head, or a female warrior's breastplate gets knocked off during a battle. The narrator usually suffers as part of the scheme.
Creed's rule "Tactical Genius"note this allows an army containing Creed to make a scout or outflank move with one unit of their choice before the game, even Baneblades and Humongous Mecha has been inflated to the point that he can hide tanks behind lightposts or outhouses.
The Alpha Legion have become this since the Horus Heresy book Legion. Some fans now reckon everything was an Alpha Legion plot.
Leman Russ in some circles of the Internet. And considering some of the stuff he's done, you at times have to ponder how much of it is memetic.
In a similar vein to Eldrad above, Asdrubael Vect is one on 1d4chan. Seriously, just read his article.
Duke Sliscus is an in-universe example. He took three ships from a rival Archon just to show off, and then hilariously Curb Stomped said Archon's best forces when he tried to get the ships back. He also completely owned fellow Memetic Badass Lukas the Trickster (the guy who can punch out Emperor Titans) in a battle of wits. Because of this, he's regarded as an absolute legend in Commorragh.
Eversor Assassins scream "WRYYYYYYYYYYYYYYY!!!" as they tear through their opponents like tissue paper.
Abaddon the Despoiler/Failbaddon the Armless, who still failed to destroy the Imperium after thirteen attempts despite having entire legions at his commands and the favours of all four Chaos Gods.
The Imperial Guard are absolutely acknowledged as some seriously hardcore individuals by real life human standards, but in fanon, they just can't shake their reputation as the Redshirt Army who get horribly slaughtered against everything else in the galaxy. Some Imperial Guard fans themselves don't mind this view, as it props their army up as the plucky Determinator that never gives up in the face of overwhelming odds.
Abaddon is typically depicted without arms, due to how the model's arms seemed to break at the slightest touch. This is combined with his Memetic Loser status to give him the titles of Abaddon the Harmless/Failbaddon the Armless.
The Squats were Put on a Bus by Games Workshop and were promptly disavowed by the company at large. Mentioning them on the GW forums was grounds for an immediate perma-ban on the first offence, with no warnings given. The extreme crackdown on all things Squat was eventually turned into a meme, where Games Workshop would send out secret police to disappear anyone who mentioned them.
Any anti-Imperial statements may result in a Commissar appearing and summarily executing the offender with their trademark cry of *BLAM!*HERESY!!!
Any and all references to the CRASSUS ARMOURED ASSAULT TRANSPORT must be made in All Caps to reflect to glorious magnificence that is the CRASSUS ARMOURED ASSAULT TRANSPORT (from this thread).
Memetic Psychopath: Khârn is an inversion, he is an Ax-Crazy lunatic that will attack anybody in canon, which is likely where the memes about him being a great guy came from.
Eldrad Ulthuan is one of if not the most powerful Eldar Farseer in the game. Fanon has him exploit his ability to flawlessly predict the future to... play stupid pranks on people (hence the phrase "Eldrad: What a dick").
Asdrubael Vect and Creed get similar reputations, and the Chaos god Tzeentch is a god of false hope and betrayal.
The Necron thief/collector Trazyn the Infinite has earned the Fan Nickname "Trollzyn", in no small part due to the "thank you" letter from him to an Inquisitor that appears on his character sheet.
In the eyes of the Emperor, Horus crossed it when he flayed a loyal Adeptus Custodes alive with a look (being the Emperor's personal bodyguards and created with individualism rather than mass-production in mind, they are likely among the most powerful of the Space Marines in general) trying to protect the Emperor during the Siege of Terra. With this, the Emperor realized that Horus was beyond saving. In early fluff, Horus actually killed a random Imperial guardsman that stood up to him but had no chance of hurting him.
In Logan Grimnar's eyes, the Inquisition crossed it when they sent the regular Imperial Guardsmen who had fought for Armageddon to forced labor camps just for having seen Chaos. After that, Inquisitors have tried to keep their distance from the Space Wolves, mostly because they're worried the Wolves will kill them on sight.
Graham McNeill for some fans of the Ultramarines, who portrays the Ultramarines as competent yet not perfect, and actually tried to tone down some of the more overt Mary Sueisms that Matt Ward put in. Ward then tried to retcon that out.
Others find that McNeill's Ultramarines veer too far into Lawful Stupid territory and hold THQ, of all people, as the ones who have most recently written the Ultramarines best, thanks to their bang-up job on the Warhammer 40,000: Space Marine video game.
On the note of writers, Sandy Mitchell, known for the Ciaphas Cain novels, is this for the setting as a whole: while other writers present the universe as an absurdly grim and utterly irredeemable hellhole, Mitchell adds familiar domestic touches such as cups of tea and rugby telecasts, turning the Imperium into a corruption and incompetence-riddled but basically functional real-life state like the US or UK, with a lot of Gothic Punk technology for flavour. Mitchell's approach is viewed fondly by many fans.
1d4chan on Rogue Trader: "Warning: Contains dangerous amounts of 80's."
The Dark Eldar were stuck using 3rd Edition models for twelve years, until they got an update (and some new miniatures) in 2010. The old models didn't age well, to say the least.
Speaking of, the game's 3rd Edition. With a tone that grimdark and pessimistic, it definitely wanted to be taken seriously, but the tone was taken so far that for many people it wrapped right round to being unintentionally hilarious.
A lot of models that haven't seen a recent update, especially the ones with swords. Just try looking at Abaddon's sword and not think of a chewable vitamin tablet.
Narm Charm: You might note the attitude of this page is that the writers are trying too hard, but we love it for that.
Nausea Fuel: Nurgle and everything and everyone associated with him.
Never Live It Down: Matt Ward will probably never live down the number of Game Breaker codexes he wrote. Grey Knights is the infamous one, not least because its Game Breaker aspects were compounded by the now-notorious accompanying fluff. He's also become truly infamous for the White Dwarf interview in which he stated all Space Marines see the primarch of the Ultramarines as their spiritual liege. It's to the point that fans speculate the reason Games Workshop no longer credits individual writers for codexes is because any book with his name on it is destined to be savaged by the fans.
The Ultramarines and Grey Knights have been accused of this under Matt Ward. Sanguinius, on the other hand, embodies many of the common traits, yet his badassery and heroic reputation leave most fans with the conclusion that he was Too Good For This Sinful Universe.
Rescued from the Scrappy Heap: Matt Ward seems to be slowly moving into this. His Space Marine codexes are generally regarded as terribad, but his Necron codex is a Base Breaker, and the Iyanden supplementary codex he wrote was actually somewhat positively received.
Gameplay-wise, Aun Va. Prior to their 6th Edition Codex, the Space Pope was useless at best and a giant standing liability to your entire army at worst, due to the then-horrible consequences of letting an Etherial die, coupled with his questionable usefulness, extreme vulnerability, and high points cost. Come 6th edition, he's become much tougher, much cheaper, and able to hand outs two powerful buffs at once to multiple parts of the army, making him, in one fell swoop, the most powerful supporting special character in the codex.
The Squats to some, especially to Games Workshop themselves (although there remains a die-hard Squat fandom who keep trading the old models and tinkering with army list rules).
The "Ultra-Smurfs" and the Tau, for both being a Mary Suetopia. But again, as with the Squats, they do have their fair share of fans.
Games Workshop itself has started to become this, due to its over-zealous defense of its copyright (to the point it's attempted to copyright the words "Space Marine"), ridiculous price inflation, continuous handing of Codexes to writers like Matt Ward, and general business dickery.
Kill points are generally hated by the fan base for being poorly balanced. Guard players hate the rule with an unparalleled vengeance because it made 1/3 of the game's missions unwinnable until the Guard players got a new codex.
The 4th edition skimmer rules received lots of hate because of the way Eldar and Tau players abused them (Dark Eldar not so much due to tissue paper armor and the fact that only seventeen people played them). Both armies could fire through them during their shooting phase and then use them for cover during their opponent's turn — their skimmers were assumed to simply elevate to allow it and descend afterward. Realistic, but BROKEN. The Tau version got the nickname "Fish of Fury". The "Fish of Fury" was considered by the 40K community at large to be so broken, that quite a few Tau players thought it was a cheap tactic. Think about that for a second.
The 2nd edition Tyranid 'strategy card' table would often screw over half the opposing army before the battle had even started.
4th edition consolidation rules were hated by shooting armies due to the chain reaction of doom that would always happen.
The 5th edition wound allocation rules are hated for being slow, counter-intuitive, and abuse-prone. More so for units with varied war gear and multi wounds such as Nob Bikers and Seer Council. The former is Unwinnable for Tau players.
In 6th edition, more and more mechanics are now randomized, rather than chosen as part of your army list (psychic powers, warlord traits) or decided upon by the players beforehand (terrain effects, whether the battle takes place at night, game length). This is magnified for the two Chaos armies (Chaos Space Marines and Chaos Daemons). Chaos Space Marine characters had a chance to disappear because they either got turned into a spawn, or turned into a daemon prince and you had no model on hand (yes, this is actually a rule). And this is triggered by them winning challenges. Daemons got hit even harder, as on top of having a Warp Storm table that could take out a quarter of their army just because the dice gods weren't happy, you now can barely choose any equipment for them; all daemonic gifts are purchased as randomized rolls similar to the Psychic Table, so you can't even account for them (except for weapons, which are the only things you can switch out gifts for).
Seinfeld Is Unfunny: Ultramarines are generic or the view the Space Marine codex devolved into an Ultramarines Codex. The issue is fluff-wise, as Rouboute Guilliman, the primarch of the Ultramarines, wrote the Codex Astartes, which is the guide used by Space Marines to dictate the tactics, equipment, and strategy used in battle. Any other chapter using those rules is generic, but even if Ultramarines had a unique codex, it would look exactly like the generic Space Marine codex. The non-generic chapters are defined by how they differ from the Ultramarines. The first 2nd Edition Space Marine codex was Codex: Ultramarines, which makes the entire situation even funnier.
Squick: The Dark Eldar live on it, Nurgle and Slaanesh are made of it, and yet they were somehow outdone by the Tyranids. The space bugs have a creature called the Dominatrix. Leave it to the Games Workshop people to come up with such a gross definition for that word.
The reaction to 6th Edition really illustrates this within portions of the fan base. The wailing and gnashing of teeth about the introduction of random terrain effects and mission objectives with strange effects is an almost textbook example. There's also been a ton of complaints about randomized psychic powers, but the rage against that part is actually grounded: psykers are often commander units who should know damn well what powers they use going into battle, and many powers are a pretty integral part of your strategy.
This happened again with 7th edition, due to the concept of "unbound" lists. Unbound means that you discard the force organization and basically take what you want, with almost no restriction (although several people will quickly point out several). The only drawback to this was that your army do not have access to any command benefits while other forces who do adhere to these restrictions (called Battle-Forged) gain free rules which could tip the game in their favor. It was literally hours within release that people started making spam lists, most infamously the "All Riptide" list. In addition, in the last edition if you wanted to take any sort of super-heavy vehicle or a gargantuan creature, you usually had to take a proper army (however small) before you could do so. With Unbound, you can literally field nothing but super-heavy vehicles from any army and their usual overpowered rules are worth losing the command bonuses that Battle-Forged armies have. Naturally, several people complained that the balance was thoroughly thrown out the window and several gaming spots and tournaments started a ban on Unbound Armies, which means people who genuinely use it to make fluffy armies are left out in the cold.
Tear Jerker: Here is the dedicated Tear Jerker page for Warhammer 40000. For a series that is so insane, its casual treatment of unbelievable courage in the face of impossible odds makes it a favorite for those who don't mind shedding Manly Tears. Indeed, there's a reason why the novels focusing on the Imperial Guard in particular are so successful, as they slap a human face on the setting and more often than not a touch of optimism and faith in the human spirit. It's the insanity of the setting that makes this so effective. This is summed up best by Dan Abnett:
Practically a warcry for the hardcore 40k fandom. The fans love to bitch about the game almost as much, if not more so, than they like to play the game itself.
Was true, however, in regard to the awful third design of Citadel paint pots (the screw-top), which would universally either seal itself with spilled paint or fail to seal properly due to spilled paint after a handful of uses. Had a happy ending, though, since eventually GW realised people were buying paint from other companies and went back to the flip-top design.
Ollanius Pius may be one of the most flagrant examples in canon. Originally, he was the very incarnation of the Badass Normal concept, an Imperial Guardsman armed with nothing more than a lasgun, flak armour, his faith in the Emperor, and balls the size of battle tanks, who took on Horus on the latter's own flagship AFTER he had just taken down the Emperor, the most powerful being known to just about every human in existence. Pius knew it was a doomed Last Stand (and sure enough, he was killed in the time it took Horus to look at him) but pressed on anyways. His sacrifice was poignant enough to move the critically wounded Emperor to action and was widely regarded as a contender for the setting's greatest Crowning Moment of Awesome. Then new lore came out and replaced him with a terminator from the Imperial Fists, then a member of the Legio Custodes. Then they brought Pius back, but made him a 30,000 year old borderline Mary Sue with Resurrective Immortality. This change has not gone over well with the fanbase.
The Imperial Guard go through a cycle of this every five years or so. They go from being hated for being horribly weak in the most popular game modes, to being hated for having some of the strongest vehicle army lists.
Daemons through most of 5th edition, especially since they have an (now extremely powerful) army designed to curb stomp them, and were long-overdue for an update.
The Sisters of Battle's magazine-exclusive codex was universally panned. Written by Robin Cruddace (who also wrote the overpowered Imperial Guard codex and the underpowered Tyranid codex), it has a number of major problems; the most major is each unit has a power of faith that can be activated by spending a faith point, of which they get a rather small pool— and the pool is always the same, small size, be the size of their army twenty women or two hundred. And since the codex was squeezed into two issues of a magazine rather than getting to fill its own book, the Sisters didn't get nearly as many new units as they really needed, most notably in their limited options for taking vehicles.
Grey Knights are a high-tier example of this. Go to the Game Breaker page for Warhammer 40000 and notice how many examples in there are Grey Knights. Or if you just want some brief examples now:
"Psyriflemen", Dreadnoughts with 2 Twin-linked autocannons with psybolt ammunition. The best long-range low-mid armour buster in the game. They can outshoot the Tau, a faction based entirely around ranged firepower.
Plasma Siphons. Render all plasma weapons, the best weapons for taking out armoured foes, useless. Grey Knights have Powered Armor as standard. Do the math. Also worth noting that the previously-mentioned Tau have plasma weapons as standard, making games against Grey Knights completely unwinnable.
Grey Knights can field up to six Flying units in a 2,000 point game. Flyers can't be assaulted, making it unwinnable against melee armies like Orks and Chaos, and they can only be targeted by units with the Skyfire rule. That gives you two options: 1) play as Imperial Guard and use a list that is only really good that countering GK flyers, 2) hope to The Emperor that your limited flyers can somehow take out their stronger and more numerous flyers, or 3) somehow wipe out all GK ground forces before Turn 2, which is easier said than done.
The Space Wolves were considered one for a while, due to basically being Space Marines but cheaper and better, as well as having one of the most insanely powerful psychic powers of its day in Jaws of the World Wolf.
The Tau have seen time as both high tier and low tier versions of this. The high tier version was largely due to the notorious "Devilfish Bunker" tactic, one of the worst Game BreakerLoophole Abuse tactics to ever hit the game, which dominated 40k tournaments the world over until the rules were changed. Some Tau players were so eager to distance themselves from a tactic they saw as borderline cheating, they completely removed Devilfish transports from their army list (in an army that really needed them) and slogged their units across the battlefield on foot.
On an individual unit note, Chaos Spawn were long considered the worst units in the game due to their terrible armour and random movement. They have since been improved. Tyranid Pyrovores seem to have taken their place in the "worst unit in the game" contention.
The Tau Ethereal was also a unit noted for its uselessness. It was not a particularly useful model at the best of time and if the opponent killed it, it inflicted an army-wide debuff that could cause your battleline to crumble. The Ethereal was noted for being one of the only units in 40k that actually made your army measurably worse by its inclusion.
Necrons and Tyranids are the primarily recipients of this, depending on how you look at it, though, every race in the setting could have been subjugated to this in some manner at one point. Part of this is the Status Quo Is God setup, since nothing ever changes, it doesn't make the factions look very good, especially given the sheer amount of Stupid Evil that can make the setting not so much come off as Evil vs. Evil as it does blunder idiots vs. blundering idiots.
Chaos Space Marines have also suffered this because they're billed as the Imperium's biggest enemies and, they've been fighting them for 10,000 years.
Villain Sue: The Necrons used to be this until their Badass Decay. Tyranids are accused of this now, since they're stated that if they win they consume everything from the loser, meaning casualties are nothing to them, Enemy Civil Wars are nothing to them — little more than an unorthodox testing session for new tactics and biomorphs — and they are stated to constantly adapt to most any new threat presented to them.
Eldar Guardians. Eldar civilians sent into battle with weak (for 40k standards) armor and a short-ranged shuriken catapult; they are used as cannon fodder and heavy weapons support in comparison to the elite Aspect Warriors.
For similar reasons, the average Guardsman and Tau Fire Warrior (at least the Fire Warriors want to be there).