If you're on a video, don't comment as to which faction you'll be. You'll get hefty praise and criticism alike, from fellow faction members and rival faction members respectively.
Depending on who you ask, the Phasing System is either the most immersive thing to ever grace an MMORPG, or its an unnecessary barrier with a complete lack of any kind of way to go back to previous phases, barring you from being able to help friends complete quests that you previously completed.
Changing the game to buy-to-play and adding a cash shop for cosmetic items (costumes, vanity pets, and mounts): An excellent opportunity for those who can't afford or didn't want to pay a monthly subscription, or the start of a poor community and pay-to-win?
Literally, in this case. Spider Daedra summon miniature spiders, and have one of the most annoying Damage Over Time abilities in the game, because it's an area-of-effect. Storm Atronachs also get special mention, because not only are they a common headache at Dark Anchors, Sorcerers have an Ultimate ability in Daedra Summoning to summon them on you, too!
The Breton from the trailers, due to his sheer knife-throwing, acrobatic badassery.
Razum-Dar from the Aldmeri Dominion is very popular in his own right, probably because he's the funniest and most engaging NPC in the Dominion.
Naryu Virian from the Ebonheart Pact is so popular that players are demanding she be brought back in a future storyline. She's a member of the Morag Tong, and easily one of the funniest and most amusing characters this side of Razum-Dar. She openly flirts with the player character on occasion (regardless of gender), and of course, she's a total badass who is one of the very few genuinely useful NPC allies you can have in battle. Zenimax is perfectly aware of her popularity, as they've actually stated they might bring her back sometime, and you can actually buy her outfit to wear for yourself in the Crown Store.
Game Breaker: The deconstruction mechanic is this for crafting. When using Woodworking, Blacksmithing, and Clothing, you have the option to take pieces of equipment for that craft and breaking them down into base components and get some crafting EXP in the process. It becomes ridiculously easy to horde loot from defeated enemies and gain tons of ore, wood, hide, and race motif items, as well as easily level up your associated skill. Even better, you can simply steal everything not nailed down in the (respawing) market stalls, not only making it trivial to gather huge amounts of resources with little effort, but allowing you to craft 'clean' items that the guards won't take from you if caught.
Good Bad Bugs: Borders on Game Breaker. Animation Cancelling. Done by exploiting the 'animation priority,' nimble-fingered players have found that rapidly chaining together a light attack, an ability, and then a bash in that order cancels the animation of the previous action and leads right into the next one, effectively allowing you to spam abilities and dish out insane amounts of DPS by negating the game's version of a global cooldown. In the hands of a destruction staff user with Elemental Drain, this can be a deadly combination, because you will never run out of Magicka. ZoS themselves have admitted that they never thought this was possible, but because it's technically not an exploit, they aren't sure what to do about it. Cue Player Versus Player enthusiasts starting an Internet Backdraft.
Hype Backlash: Given that the game was heavily advertised for a few years, and had its admittingly epic looking cutscenes shown, many fans felt ready for an Elder Scroll MMO. When the game came out, that hype turned into Internet Backdraft for the game's issues and the fact that it has considerable differences from a main-series game.
The initial subscription fee caused this, since it meant players had to pay to play the game they just bought, in addition to the monthly subscription fee.
The Imperials being both in the game, and only available if you buy the Collector's edition caused a massive issue with fans, since it both ignored the lore, and just gave more reasons to give money to the game.
Early on, the lack of money, auction houses, or good player economy really made a problem with players because gold was so hard to come by and there was no real economy for players to work with. This was alleviated by adding guild stores and the Justice System (which made gold MUCH easier to come by).
The Steam release of the game. Zenimax announced several times on the official ESO forum that the existing version of the game is not compatible with Steam and can only be added as a non-Steam game, and only new accounts would get the benefits of having it on Steam, such as the trading cards. They also released a special dog vanity pet (one of the most asked-for pets) for new accounts made on the Steam version - and new accounts only; it wasn't a code that could be applied to existing accounts if one were to purchase a second version of the game.
Changing the game to buy-to-play and adding a cash shop. Many players dislike the idea of a cash shop in particular, fearing that it might mean pay-to-win (and if not, you still have to pay to get "all" content in the game).
"Transcription Error" has slowly become a popular one. To elaborate, the game developers made a haphazard retcon when making Cyrodiil into an European temperate grassfield as seen in Oblivion instead of the rainforest it was depicted as at that point of time, which the game developers handwaved by essentially calling Pocket Guide to the Empire, the key source of information on Tamriel, false... even though there are numerous books and even firsthand accounts by NPCs that say otherwise.
"Oh, look at that! Two gold coins!" became a popular joke on certain forms and videos where players would loot a boss or quest boss and find more than just a single gold coin.
"Stay moist" is something you'll hear players say occasionally; it's a phrase that Argonian NPCs say.
Misblamed: One of the most common complaints about the game is the idea that Bethesda won't have any time or energy to make a new single-player Elder Scrolls game if they're busy with an MMO. That might have some validity... if the game wasn't being developed by Zenimax Online, Bethesda Game Studio's sister studio under the Zenimax LLC group. It's possible gamers were thinking of the Warcraft RTS series which did get put on hold for World of Warcraft. Zenimax LLC deciding to set up a separate company to develop an online Elder Scrolls game was likely done to keep such a situation from happening. Bethesda Game Studios having no experience with MMOs was probably another factor.
Spiders make an obnoxious noise when they detect you.
Nightmare Fuel: The end of the Arrival Trailer has the corrupted Breton and an army of undead take the capital of Cyrodiil by surprise, with Molag Bal's face smiling diabolically in storming clouds in the background.
Paranoia Fuel: During PVP in Cyrodiil. The map itself is huge and there are plenty of places in Cyrodiil to explore, but keep in mind that you can be ambushed by other players at any time... any time.
Pre-Order Bonus: Players who preordered the game got the Explorer's Pack, which gives you the ability to have your character be in any alliance regardless of race, a Scuttler vanity pet, and treasure maps.
Rescued from the Scrappy Heap: To a extent, the High Elf race was. After Skyrim where they were both In-Universe and Meta scrappies (or at least those associated with the Thalmor were), a lot of players enjoyed their quests due to the approach the Thalmor go to to win the trust of their allies (such as basically saving one city when it's attacked) and some likeable High Elf NPC's that stand out.
Early on, extremely low money drops. Many enemies only drop a single gold. Bosses tend to drop only a few more than that. To put this in perspective, before mounts were overhauled to make different horses cosmetic, a passable horse cost about 20,000 gold and a good horse cost about 50,000 gold. If you can't afford a horse? Have fun walking across the map to the next city. It was to the point that if you wanted a horse you had to either grind for hours and hours, or upgrade to a collector's edition, essentially Bribing Your Way to Victory. Much improved by the Justice System, which made gold much easier to come by (common items are 40 gold, rare ones are worth a couple hundred), the price of the cheapest horse being dropped to 10,000, and the overhaul of the mount system, which made stats based on the character rather than the horse itself so that you didn't have to, say, buy a 40,000-gold horse to get a speed bonus; the cheapest horse would work exactly the same way.
No player houses. Given that previous games offered everything from small shacks to mansions this has upset many players. Zenimax did confirm that housing is coming, they just want to "do it right."
Quests progress individually for each player. This makes grouping both tedious and completely pointless. This also means fighting over loot since treasure doesn't respawn for each character in the party.
Because of the way classes are set up, it's entirely possible to have a spec set up that makes you unable to deal sufficient damage to enemies.
The trait system for item creation. 9 different traits can be applied to weapons or armor when forging them. Per item type. For those that want to collect all the traits for all the items, you're looking at 306. Tedious but doable, you say? There's a timer that is required for researching those traits in the first place. Researching a trait for a specific item & slot DOUBLES the research time of the next trait for that item & slot. Starting at 6 hours and going from there, you're looking at a total of sixty three days for mastering every trait ON ONE ITEM.
The Tel Var Stones currency that comes with the Imperial City DLC. Most enemies in the Imperial City only drop a few and the prices for items range into the thousands. If you're killed by a monster, you'll lose 10% of them. But if you're killed by any enemy player, you'll lose ALL of them.
Tainted by the Preview: Some fans got increasingly excited for new info and news about the game, whereas other fans got increasingly more disappointed.
They Changed It, Now It Sucks: The choice to make the game a MMO instead of a single player game was the biggest criticism amongst its fans. This is, however, a case of Misblaming, as it's being made by a different studio rather than Bethesda Game Studios and therefore does not affect the release of the main-series single-player games.
Doshia in one of the Fighter's Guild quests before she was nerfed. Doshia could be immensely difficult at low levels despite the quest being aimed for low levels. It was highly recommended that you fight her at a level 20+ because if you're any lower she would've absolutely mopped the floor with you. Part of the reason was because many players didn't realize that they needed to kill her healing bubbles in addition to Doshia herself, but she still wasn't an easy boss to any extent.
Gutsripper from the Mage's Guild also stood out as a giant pain in many asses before he got nerfed as well.
Praxin in Veteran Spindleclutch. If you didn't think Spiders Are Scary before, you will. The Zerg Rush of little spiders at the beginning is bad enough without the three more waves that follow, and sometimes, it will even bug out causing all of the waves to come at once, essentially making this boss a Luck-Based Mission.
Veteran City of Ash. Oh, where to even begin... in order to get the 100% Completion achievement for this dungeon, you will need to run it at leastthirteen times to get all of the Flame Colossi, and that's not even counting the Nobody Dies achievement, which you basically be a team of That One Player's to get. God help you if you're a vampire.
Veteran Maelstrom Arena. It's a solo-challenge, and it's an eight arena-long marathon where you're up against enemies that hit like a truck and deal a LOT of damage. You can only resurrect 500 times, which sounds like it's plenty... until you find yourself dying every single round. To be fair, this is meant to be the ultimate test of a player's ability, and if you happen to get the title of "The Ultimate Conqueror" for clearing it without dying once, congratulations, you are officially That One Player.
That One Sidequest: The Hidden Harvest quest for the Orsimer DLC requires you to destroy a Briarheart Tree, which sounds easy in theory but it's continuously healed by Briarheart Tree Tenders, which respawn as soon as you kill them. Add in being constantly immobilized and throw in a heaping helping of other enemies and you've got a recipe for an unbeatable quest.
Unfortunate Implications: On a meta level. On the ESO Live Podcast (skip to 00:35:20), it was admitted by Zenimax that lately, they've been using only one model for new armors instead of two. Previously, they would make two models - one male, one female - for every single piece, to keep the armor consistent with, well, anatomy. Instead, they've been using only male models, and then morphing it to look 'feminine' afterward, as a way of cutting corners. Cue a thread hundreds of replies long blasting Zenimax for cutting corners like this at female characters' (and players') expense, for the sake of Money, Dear Boy. Much like the debacle over Assassin's Creed: Unity, female players feel cheated, and are actually offended that they did this to them but left male characters alone. Zenimax has already responded to the backlash by promising to fix them.