I've got two.
1. I'm tired of character death being used as a cheap plot device on television and in films. While I don't watch the show, I read an article today about last night's episode of The Good Wife, wherein they apparently killed some high profile character. So as not to spoil it for anyone, I won't go into further detail, but the article made a pretty good point about how pretty much EVERY show does this now and it is not at all meaningful anymore. I think this extends to film as well, where some "surprise" death comes out of nowhere just to hit a beat or show that "we're serious" or whathaveyou. In some cases, it fits with the story, and that's fine. But when it's used as a crutch or as a substitute for doing the harder work of telling a meaningful story about life WITHOUT resorting to death as a prop, that's when I have a problem with it.
2. Related to #1, the overreliance on "dark" as a theme. It's fine to have gritty, grim films. In many cases, that's appropriate. But particularly for certain subject matter, it's really inappropriate and out of place. What's more, it's fast becoming generic (along with muted color palettes) in comic book films, even when the subject matter doesn't call for it. I think the "dark" thing is actually missing the point, though, and is overextrapolating from the success of the Nolan bat-films. I think what audiences appreciated about those films was (1) that the films took their audiences seriously and treated them as intelligent humans rather than idiot children, and (2) that the world felt...hmm...grounded. Somewhat realistic (yes, in spite of some of the more glaring unrealistic aspects).
I think this is one of the things that, by contrast, Man of Steel so screwed up (along with really bad pacing). It tried to be too serious and grim with material that is, traditionally, not as grim as all that. I still think that you can do a Superman movie that takes its audience seriously rather than condescends to them, but still has an upbeat, positive, view of the world, and is visually bright and colorful instead of generically drab.