Maybe it is the wastefulness of remakes to which I object. If the first films were fine, why mess around and waste money making another? Other than the obvious answer of 'make more money for the studio'.
However, my main chagrin has to be the lack of continuity and the sense that the makers don't really like the subject of the films or respect its fans enough to keep facts straight.
I know how hard it is to plough through material and make sure the argument is cohesive, avoiding repetition or omission that might change fundamental parts of the cannon. Perhaps I'm naive in assuming all official output has to be cannon, but for me it does. If the original creator or whoever owns the rights now says, "Yes, make this new comic/book/film/doodle using the content/ideas/characters that have previously been used." Then I really do expect there to be a shared sense of responsibility to make the new material sync with the previous; not just thematically fit, or 'you could see how someone would think that would be sort-of appropriate' - I want it belong cogently and cohesively in the same universe. I don't want a mind-fog moment of 'erm, I might be wrong but didn't she used to wear red shoes when she was in fighting mode' and then have to endure either of two equally insupportable situations:
1. Watch the movie assuming they are right, that your brain has somehow melted rendering all previous stored information muddled and worry about your ability to remember the order of door, lock, lid, pants, sit, wee when the occasion arises...
2. Watch the movie assuming they are wrong, that they couldn't be bothered or had insufficient resources to properly research the previous output and worry about what other jarring inconsistencies may arise before the film concludes, releasing you into the sweet freedom of wiki checks proving that yes, you did remember that inconsequential detail correctly.
N.B. This is similar to my worry about live performances where a small dance misstep or incorrect chord or forgotten line can ruin the experience for me and leaves me on the edge of my seat with nervousness before the performance has even begun. I cannot even bear the anticipation of errors, I am involuntarily but irretrievably mortified on their behalf, guilty of aiding and abetting their mortification by choosing to view this performance and thus forcing them to present themselves for judgement by an audience (only one of which is me). It is irrational but unavoidable.
For those wanting a tiny taste of the furore that can be created when cannon is disrespected, please check out this X Men link which hints at the consternation bubbling away on the interwebs.