I seem to be in the minority ... but I liked the trailer quite a bit.
I really like the concept of the civil libertarian foreigner Superman against the paranoid lawless vigilante Batman. Great angle, and a clear explanation of why they dislike and distrust each other so much. That explanation has to be included in a trailer. Casual moviegoers may genuinely not understand why Batman and Superman would ever be fighting one another. That conversation between Wayne and Kent was great. I got the feeling Wayne knew who he was talking to ... but Kent didn't.
Several really cool lines. "That SOB brought the war to us." "If I wanted it, you'd be dead already." Affleck is on point. Great costume. Great armor. Great voice. Great characterization. Batman as borderline 'xenophobic' (as someone else said earlier) is a completely logical characterization. Never been a huge Wonder Woman fan, but she looks good enough. I wish they'd've just left her for some end-credits thing or a later movie, though. I think the BvS angle is enough for one movie without bringing in the B-team.
I agree with a few criticisms, though. It's WAY too spoiler-heavy -- should've only hinted at Doomsday, and left the WW shield save out of the trailer completely. End the WW clip with the "oh, $#!%" and a growl/eye blast/explosion.
I also agree that Lex Luthor is off -- with the notable exception of the "... the devil will do it!" line. That sounded great. Seething, growling hatred. That's Luthor. So, even though Lex was way too goofy at the party, I'm optimistic it maybe he was just playing a public character, and he's privately the unapologetic, not-at-all-cutesy villain we all hope he is.
And, I'm not totally sold on Doomsday's look. It's not awful. It's just a bit too Abomination-looking. Maybe I'll change my mind, though.
As for the Marvel 'tone' of the trailer ... it's a trailer. You can spin whatever tone you want in a trailer, and Marvel sells a lot of tickets. Particularly to families. I don't necessarily think that'll be the overall tone of the movie, though. Batman's characterization, the authoritarian Superman jackboots (fantasy or not), the Kent/Wayne conversation and Batman vs. Superman fight look plenty dark ... and very un-Avengers-like.
I remain optimistic.
Oh, is Kryptonite a thing now in this universe? I guess that would make sense.
Not yet. I'm guessing Bruce Wayne discovers it (though maybe Luthor). Which makes a hell of a lot more sense than Reeve's Superman revealing his Achilles heel in a newspaper interview.
SnakeDoc