I am a Batman Vs Superman skeptic (an easy thing to be these days), but Den of Geek has an interesting theory:
One of the major gripes audiences had with Man Of Steel was in Superman's apparent lack of concern for Metropolis' inhabitants, with the hero seemingly ignorant of the fact that during the fight between he, Zod and the other Kryptonians, carnage and death was occurring everywhere. And yet this very destruction could be the key that drives forward future DC films, beginning, of course, with Batman Vs Superman.
Imagine if you will, that a battle-hardened Batman arrives on the scene and is witness to the rubble and large scale carnage within Metropolis. A hero whose morals cause him to disavow murder, the Dark Knight attempts to turn the government against Superman and consequently starts a war between them and the Kryptonian, who's looking to find a place for himself among human society.
My complaints about Man Of Steel were several, but the "major gripe" detailed above did not really bother me.
Primarily, I didn't really care about any of the Jor-El/Krypton backstory. It was far too convoluted, took up too much screen time, and was more interested in production design and special effects than actually telling a compelling story.
Beyond that, once the destruction started with the big fight in Smallville, I largely lost interest in the goings-on. At first, it was neat to finally see a Superman movie with visual effects up to the task of showing super-powered Kryptonians punching the shit out of each other. After the twentieth time someone threw a truck or leveled a building, though, who cares?
Finally, I found the whole business of Zod to be tiresome and lazy. Yes, everyone loves Zod as the villain in Superman 2, but how about doing something we haven't seen on the big screen before? I don't care–Darkseid, Brainiac, hell–I'd even take Mr. Mxyzptlk at this point. Just stop relying on the audience's nostalgia for the old movies.
Most of those problems I lay at the doorstep of Zack Snyder, a director not generally known for his subtlety. It would actually be pretty cool if Den of Geek were right, and this were the direction Batman Vs Superman was headed. However, I don't really trust Snyder not to get distracted by throwing in more explosions and close-ups of snapping bones. More generally, I see no evidence of DC playing a long game, beyond "Oh shit, we need to get to Justice League because Marvel is eating our lunch!"