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.
It's a common game to find proof Luke's on the dark side. Citing Dark Empire is cheating.
Palpatine's running of a brutal dictatorship and commission of numerous atrocities and superweapons: preparing the galaxy for the Yuuzhan Vong invasion, or convenient excuse-mongering from the losing side? Or even more alternately, preparing for the YV invasion because "they're gonna take my stuff"?
Vergere is made for this, because she deliberately refuses to be pinned down as any one thing. Is she a heroic Trickster Mentor, a scheming evil Chessmaster, a broken individual trying to make up for the mistakes of her past, a loyal but unorthodox Jedi of the Old Republic, a Sith Acolyte, or just crazy? You can find support in the text for all of these, though admittedly some more than others- the reader is left to draw their own conclusions. Recent books have been trying to hammer in the "Vergere was a Sith!" interpretation in order to support the Legacy of the Force storyline.
Anvilicious: Luke constantly telling Cade that drugs are bad.
Better Than Canon: When Children of the Jedi came out, most fans preferred Luke with Mara. Of course, this later became canon. Also, some fans would like to leave Chewie's death and everything afterward out of canon.
Tellingly, George Lucas did not specifically exclude Chewie from dying. There's a rule that the death or marriage of any of the major characters from the movie trilogy had to be run by Lucas first, one of the few times Lucas even deals with the EU. Luke's marriage was something snuck past Lucas at the last minute, after Lucas had already turned it down. Needless to say, he wasn't happy about it when he found out.
Even more violent and vitriolic than the argument over the quality of the Expanded Universe is the argument over the canonicity of the Expanded Universe. How bad did it get? Let's put it this way: when the Non-Canon side of the argument pointed out that George Lucas himself, the creator of Star Wars and the Presumed Voice of God when it comes to Star Wars (at least one would think, anyway), doesn't consider anything other than the films to be canon, the Pro-Canon side of the argument's response was to marginalize Lucas's opinions as unimportant in the overall scheme of things since "he really has no say in the matter", a view Lucas apparently finds rather funny and, naturally, dismisses out of hand as ludicrous.
Lucas has stated that the Expanded Universe is valid unto itself. He clarified this when he stated that the Star WarsExpanded Universe is a separate entity from "official" Star Wars material, and has a canon and internal consistency all of its own outside of "real" (his words) Star Wars canon. The Pro-Canon EU fans didn't take being told that the EU was essentially a "side project" very well, either. (The Pro-Canon EU fans can be overzealous sometimes).
I am Vestara Khai, daughter of a proud heritage. I have what is necessary to command the dark side and bend it to my will. To use it for the good of the Tribe, and the People.
Any Jedi espousing the Potentatum philosophy gets retconned as this, or falls to the Dark Side. Hell, any Force user that offers a slightly different take on the Force usually is hit with this; sometimes, they have wildly different philosophies and shifts in characterization from before and after the canon retroactively decides they're evil.
Cronal has appeared in one old comic, one novel, and a handful of online and gamebook articles- but is widely regarded as one of Palpatine's most powerful and chilling minions.
Nom Anor, probably the most popular new character introduced in New Jedi Order.
Nen Yim. Though not so much as Nom Anor, she's pretty popular among a certain subset of the fanbase (especially among the general Vong-fans).
Darth Talon probably has the most merchandise and publicity of all the Legacy characters. Here's a hint, it's not because of her winning personality.
Emperor Roan Fel.
Fan Dumb: "George Lucas's opinion on what is and is not canon in Star Wars might be an interesting piece of trivia, but in the end Lucas has absolutely no say in the matter. It's not up to him what is and is not Star Wars." Yes, this was actually said. By Chad Barbry, founder of Wookieepedia. When George Lucas heard this, his response was simple: "Well, everyone's entitled to be wrong at least once in their lives."
Magnificent Bastard: The Sith Emperor spent almost 1300 years developing his plans and managed to deliver quite a beating to the Republic and the Jedi.
Thrawn is the definitive example of this trope in the Star Wars EU.
Lumiya is personally responsible for nearly everything that happened in Legacy of the Force. Her motivation is never stated outright, but it's implied that she did it all just to fuck with Luke Skywalker and ruin his life. Talk about Evil Is Petty!
Darth Wyyrlok III
Mary Sue: There are a few that may qualify, but mostly they're Depending on the Writer. One of the main base-breaking examples is Mara Jade, who exhibits many of the required traits: She's important in the story, possesses unusual physical traits, is ludicrously and irrelevantly over-skilled (pilot, slicer, tactician, combatant, spy, dancer, Jedi master - even surpassing Luke in sensory perception) and has an over-idealized nature (being all at once snarky, physically tough, warm, beautiful, calm under pressure, devoted wife etc). Most infuriating however, is that her very existence as the "Emperor's Hand" diminishes Darth Vader, who was always thought to be the Emperor's main Badass...until she came along (and even later it was established Palpatine had several Hands, each believing themselves to be unique). She also has a highly Sue-ish name, as well as having the rarest color combinations found in humanity.
Corran Horn. He's an ace starfighter pilot, who is also a Jedi. Not just any Jedi, though, but a Jedi with a unique set of powers! (Which, to be fair, come at the expense of him not being any good at telekinesis. But still.) He was retconned into the Jedi Academy Trilogy to serve not only as a mouthpiece for the Stackpole, but to just seem more awesome than any of the other Jedi and battle Exar Kun almost completely by himself. Later, in NJO, he's the one who duels the enemy leader with the fate of a planet at stake, and wins. When the Yuuzhan Vong go back on their word to spare the planet in the event of Corran winning, he gets all guilt-ridden about it even though it wasn't actually his fault, and makes the "noble" decision to go into exile so as not to tarnish the reputation of the other Jedi with his mere presence.
Fanon states that Daala is completely incompetent and only got her admiralty by sleeping with Tarkin. In the books, she is portrayed as remarkably incompetent, with the occasional Take That to the audience who thinks that way.
Moral Event Horizon: When Ulic Qel-Droma kills Cay. Which then causes him to cross the line back from the other side almost immediately.
Chantique mocking Zayne after Snout's death. And her manipulation.
The Mon Calamari massacre to Darth Krayt.
Raana manipulating Shel into trying to kill Zayne. After that pretty much any sympathy the audience had went out the window.
Acenscion contains a rare example of a character crossing their ownMoral Event Horizon. After several books of UST, Vestara Khai finally starts a relationship with Ben Skywalker and expresses interest in turning to the Light Side. Later in the book, she, Ben, and a Red Shirt are sent on a mission, during which an alien predator goes after Ben. Vestara saves him by feeding the Red Shirt to the monster. This causes her to label herself as irredeemable.
Narm: Not nearly as much as in the movies. Even so, it's there, though of course Narm Charm applies.
Raana's appearance after she and Zayne get Lacerated.
OT3: Denning likes to imply as much about Jenna, Zekk, and Jag.
The Scrappy: There are many, as expected from such a large verse. Jacen in particular can't seem to catch a break — in the early NJO he got fan hate for being ineffective, whiny, and totally unlike his YJK personality; mid-to-late NJO got him accused of being a God-Mode Sue (though this was probably the period where he had the most fans); Dark Nest through early LOTF was where he started being an epic Knight Templar and Jerkass; and now fans are angry he got killed off before having a chance to make his mark as a villain (well, he did kill Mara, but that just made fandom hate him even more).
Creator-wise, Kevin J. Anderson gets a lot of hate for Darksaber (and, frankly, pretty much anything else he's written, especially involving the pathetic Admiral Daala. But don't take our word for it — go ask a Dune fan.). Also, Karen Traviss gets a lot for talk about clone slaves and her hatred of Jedi.
Actually, the Mandalorians, as written by Karen Traviss, qualify as a Creator's Pet. 1. They are not particularly likeable to the readers. 2. Karen Traviss loves them to death, and everything she does with them boils down to shilling, as well as using this group as her Author Avatar. 3. They butted into a lot of big scenes, and the reasons for that were very weak at best - the three books written by her in Legacy of the Force are the most egregious examples. The other authors out there are well aware of her protrayal of this group.
Unfortunate Implications: The portrayal of democracy in most of the EU is comically negative, while dictatorship and authoritarianism are portrayed in a much warmer and sentimental light. In a series that emphasizes that governments should protect liberty and freedom, governments that do neither are portrayed, especially in more recent works, as inherently more functional than those that strive to do both.
Villain Decay: Darth Nihil was very intimidating in his first appearence. Ever since then he's become more and more of a whipping boy.
Despite Daala's track record of getting her own ships destroyed at little cost to the enemy, she's somehow become regarded as the second coming of Thrawn. By the end of Legacy of the Force, the government apparently thinks that giving her the most powerful position in the galaxy is a smart move.
Tarkin blew up a planet? Kyp blows up a whole system! He's actually presented as more powerful than Luke, though Word of God changes that.