Not sure how unpopular this opinion is, but I have certain grievances with some anime movies that are based on longer-running series. These are dated examples, but I'm thinking of the Bleach and InuYasha movies.
For one thing, both of these sets of movies tries to basically shoehorn in every character and their distinctive elements, even when they don't necessarily need to be there. For instance, in basically every Bleach film, you can count on the fact that every captain is going to use his/her bankai, and every character is going to use his/her strongest move, even when they're going up against the weakest of their enemies. Similarly, in the InuYasha movies, you can bet that Sesshomaru and Kikyo are going to appear in every film, even if they hardly do more than observe the goings-on and maybe dispatch one enemy that has strayed from the fight somewhere. I understand that there's an appropriate and understandable desire to ensure that the fans of all the characters get to see their favorites on screen, but when you can tell that that was obviously the only reason why a character is appearing, it just strikes me as a poor writing choice. It would've been better to re-work the plot to give all the characters a legitimate role.
The other thing is the great OP-ness of the enemies in these films. Bleach is really worse for this--in each film, the stakes are usually basically the end of the world. I get that you need to make the movies appropriately weighty, but baddies on that level were only found in the absolute primary antagonists of the respective series (i.e., Aizen and Naraku); even the individual arcs of Bleach/InuYasha didn't feature stakes that high/enemies who were that powerful. If you watch these films one after another (which, admittedly, isn't how audiences would have originally seen them), the effect is actually a little comic, seeing all these uber-powerful foes/uber-dire situations one after another, since it gets a little unbelievable.