I’ve seen many websites suggesting Darkseid, Brainiac, Doomsday, Lobo or other extra-terrestrial foes have to be the main villain within this next installment of the DC Cinematic Universe. I think this would be bad pacing for the franchise as a whole. “Man of Steel” and its final battle scene between Zod and Superman would have been arguably the most epic event in that Universe’s history. Not only did that event prove that aliens do in fact exist and are God’s among humans, but they also destroyed one of America’s iconic cities. Bringing in another Alien threat would cheapen the affects of Zod’s attempted invasion. This cinematic universe has the opportunity to paint Superman as a truly polarizing figure (Savior vs. Overpowered alien threat) unlike most other incarnations.
This is why I believe Lex Luthor has to be the main villain in this movie. Lex Luthor could be the man to rebuild Gotham and be the “common-man” savior next to Superman. I also believe that it could be fascinating to see the Lex Luthor vs. Bruce Wayne dynamic in the board room as well as in the battlefield considering the fact that Lex Luthor is essentially Batman’s villain counterpart (obviously Owlman and Prometheus are closer, but of the popular DC villains Lex Luthor is the closest). I think Batman and Superman should be fighting against each other for about two-thirds of the film because Batman has been observing since he first became a public figure and thinks he’s too powerful to not have a check to his power. Maybe Bruce Wayne and Lex Luthor create Metallo together until he realizes that Lex Luthor is a sociopath and then Batman approaches Superman and realizes that he isn’t the real imminent threat, it’s Lex Luthor.
These are just my thoughts. Let me know what you think.