X-Men: The Last Stand: Guys, why the hate?
Tempers settled after time and DOFP, but there are so many reasons to hate TLS. Just going by character:
Logan - Does the best of the lot, though generally at the expense of other characters. Gets a boring arc about learning to work as a team, then stops the final threat by himself.
Jean - The Dark Phoenix Saga is boiled down into a duel-personality sub-plot. Jean has practically nothing to do in the film and barely any lines. Considering she kills her lover and surrogate father in this film, we never really get in to the emotion of that struggle. We never even see how she feels about the Cure, something she goes to war for, only to stand around.
Storm - Storm is involved in a lot of this film. But she doesn't really
do that much. She is woefully under-written, which is most notable when you consider that Jean is a long time friend, yet Storm doesn't seem to care at all about her.
Charles - The film never tackles the morality of his actions with Jean. Logan of all people is the only character to question his ethics, in a brief spat before Charles is killed. He is then mourned as a hero and everyone moves on. He's also uncharacteristically snippy.
Cyclops - Killed super early, off-screen, and barely even acknowledged after. Characters hold a funeral for Charles immediately after his death, but don't even bother with a headstone for Scott, who died sooner, until later on.
Rogue - Sits out the film to queue for the cure, then actually takes it.
Nightcrawler - Gone.
Magneto - Ian McKellen still crushes it, but this Erik is a little more callous and stupid. He ditches his most loyal ally after they took a bullet for him, regards fellow mutants as disposable 'pawns', entertains using Jean as a weapon after witnessing her obliterate Charles but still proclaims "What have I done?" in the final moments.
Mystique - Small role before being cured and replaced by less interesting henchmen.