Like, I was frustrated by a lot of storytelling blunders, and sidenote I don't care about liberties they take with these characters because the source material history is so rich that there's so many different incarnations of these characters that you best believe there's incarnations who aren't like "our" definitive versions (our favorite versions I guess).
Sidenote, that thing you think Batman wouldn't do, I can bet you right now there's an incarnation of him within the DC Universe that would do exactly that, and that's why I could never get hung up things like "Superman doesn't kill" or things that are specific to an incarnation of these characters because the comics themselves don't get hung up on those things as they keep redoing canon at intervals. In fact, I'd say the character stuff in the movie was great. Batman/Bruce Wayne* (might be my favorite cinematic Batman in terms of how he was portrayed), Superman/Clark*, Lois, Alfred, Perry, etc (expect Lex Luthor bothered me though for numerous plot related reasons).
*I include Bruce and Clark in this because they add to the character related progression of the alter egos in the movie.
My problem was that this was too dense a movie in the sense that were 5 stories being told and not enough focus on any of the threads for me to care or be invested, no real narrative structure giving the movie real forward momentum. Like so many cool things happened but throughout the movie I kept asking myself "what's the actual plot?". And it wasn't because there wasn't a plot, there were just too many plots that weren't serviced into a great narrative. The movie expects so much from a fan in terms of suspension of disbelief, and tries to sell on certain things in the story that just aren't earned in the narrative (don't get me wrong, a lot of it is cool but it is no way earned).
Also, the universe building stuff was SOOOOOOO FUCKING COOOOOL!!! But at the same put into the context of the movie was distracting. Man, mind is all over the place on this one. I need a second viewing to wrap my head around what my coherent thoughts are.
There were good ideas moving the movie, but there wasn't a real narrative that was given focus. What plot

? Here, have all this fan service!