Not really a villain, but Azrael would be nice.
Does anyone else think that The Joker and Catwoman are already in? Im not sure there pretty popular, they were in mk vs dc, they were in batman arkham city, Catwoman has her own comic, Joker was in batman arkham asylum
Bane would be the greatest grapple character ever. if he makes the roster i have my main I've loved him since the early 90's