2. Lex Luthor
Let's be honest, if DC choose to go with any villain other than the bald phenom, it will be a major shock. The hints were there in Man Of Steel that Luthor would appear in the sequel, and dropping those pointers now would be stupid. Luthor is of course Metropolis' most enduring villain, cunning and super-intelligent, and the antithesis of what Superman represents. He is Superman's counter-point, and the comics have established that Luthor and Bruce Wayne have a long-standing professional rivalry, which could perhaps explain Bats' sojourn to Metropolis.
Why He'd Suck Just to clarify, Luthor as a presence in the movie, setting up further storylines would be a smart idea, but Luthor as the main villain would suck, because it'd be too much, too soon. Luthor needs to be set up before a grand malevolent plan starts to brew: he needs to be presented as a puppet-master before he is revealed as the big bad of a film. And equally, because he is Superman's arch-nemesis, the idea of introducing him as the villain in a film sharing focus between Batman and Superman would be to cheapen the relationship between Superman and Luthor.