6. Prometheus - Damian Lewis
Much like Hush, Prometheus is an intriguing potential for a key villain in Snyder's DC universe because he is the antithesis of Batman. Even more than Hush, Prometheus is a direct mirror, the son of criminals who vowed to take down all forms of justice because of the deaths of his parents, and used their hidden wealth to travel the world learning the ways of master criminals. Damian Lewis would be a particularly intriguing prospect: he has proved in both Band Of Brothers and Homeland that he is more than capable of the same sort of leading man presence of the likes of Ben Affleck, and in the latter his darkly appealing charisma sold his villainous and ambiguous moments brilliantly. If Snyder and co decide to go with the Prometheus storyline - which would represent a significant threat to the entire JLA - there of course would need to be another key casting to complete Prometheus' famous character arc in the comics, since it is a character outside of the JLA who brings about his first defeat.