I'll give the film credit for its basic idea. If someone like Superman really existed, there would be controversy on a social, political, and personal scale - great fodder for nuanced storytelling. Unfortunately, Batman's reasoning for taking on Superman are paltry at best. Even if there's a 1% chance for Superman to be bad, he claims they should take it as an "absolute." Okay, I don't know much about Bruce Wayne, but logic or math do not appear to be his forte here. In the first scene, one of Wayne's buildings is destroyed in the battle featured in Man of Steel, killing one of his employees (his name was Jack, but for the first few times I kept hearing "Dad" and I was really confused). If it had been his dad who died in the destruction, it would better justify Batman's rampant killing and irrational, impassioned opposition to Superman. As it stands, Batman dislikes Superman because he's too... super? I don't even know.
Another character I couldn't understand was Lex Luthor, who turns out to be yet another boring and flat villain. Hollywood has not gotten a handle on how to create complex antagonists, especially in superhero flicks. I couldn't tell if Luthor hated Superman, Batman, or both for most of the movie. Even when he reveals his "master plan," his various schemes fall apart pretty quickly and I never felt much suspense. Luthor himself acts stereotypically "psychotic," as Lois Lane calls him, in a way that contributes nothing to portraying him or mental health in a complicated fashion. It was so easy to write him off as "unstable," and I hate even saying that because he still could have been an interesting human character. He just wasn't treated that way. I'm sure the comics do Lex Luthor way more justice.
As for Superman, his characterization (if you could call it that) ties closely to Lois Lane - AKA a shameful waste of Amy Adams. Their "epic" romance is encapsulated in the several times he rescues Lane from certain death - a classic damsel-in-distress formula to make the superhero look awesome and to give him a meaningful motivation. Yawn. At least we had Wonder Woman! For like, three or four scenes. I liked her badass fight skills, but despite this, she didn't do all that much. I did like the part where Superman asks Batman "Is she with you?" and Batman replies, "I thought she was with you." She's not with EITHER OF YOU, PUNKS! Glad she's getting her own movie.
I mentioned the dream sequences, which are all in Batman's perspective and are all extremely unnecessary. To be fair, I didn't like the dream sequences in Age of Ultron, either. The only purpose they seem to serve in both movies is to set up for future movies in the most confusing way possible. They failed to contribute to the story or Batman's characterization in any meaningful way. (I even stepped out to go to the bathroom during one of them.)
Batman v. Superman did not make me excited for future DC movies. If anything, it made me nervous about Marvel's Captain America: Civil War. BvS shows us how a battle between superheroes does not necessarily equal a great film, good storytelling, or even decent characterization. Perhaps I could have appreciated the movie better if I'd already possessed a taste for DC's distinct style of comics and heroes. However, as it stands, I could live without seeing any more of Batman or Superman.