7. Amazo
Because the name is just so damn fun to say. No, but really Amazo could make combat in Injustice reach a whole new level. An android with the ability to duplicate the powers of the heroes and villians with whom he comes in contact, Amazo is set up perfectly to be the Shang Tsung of Injustice. Oh, he has also not only been an enemy to, but a member of the Justice League as well. In a game with a story as bleak as Injustices there is so much room for moral ambiguity to an almost noir like level. Bring the guy who has fought for both sides into the fold of a warring Justice League and things could really step up a notch. This is another character who could allow an expansion to both the storyline and gameplay of Injustice, and could create for some great multiplayer match ups.