Hmmm....well you'd want a more aged Batman than Josef Gordon Leavitt if he's going to be opposite Superman, you kind of want a wizen Batman but also one who is a bit well you don't know if he's sane or not...kind of in the Michael Keaton/Christian Bale mold.

Perhaps Jonathan Rhys Meyers, Michael Fassbender, Joaquin Phoenix, Josh Brolin, John Hamm


Just my take