Re: Next Batman Villain?
I think The Black Mask would be a good choice for a Batman movie. Have the movie be about Batman trying to learn the Black Mask's identity, after several murders committed by the False Facers. The average person would have no idea who it is, and the movie could introduce both Jeremiah Arkham and Roman Sionis as possible suspects for the comic fans out there.
Anarky could be another interesting villain to see eventually, although not as the primary antagonist.
I would save the Joker for the third movie, similar to how Iron Man did the Mandarin.