I am hoping for a secondary villain who can can challenge Batman physically in the next film. I for one am not on the bandwagon that hates Nolan's from the shadows camera work on fight scenes; it works for the narrative of Batman, but that being said I'd like to see someone who can offer a more sustainable fight scene. I want someone who pushes Batman to his limits before Bruce picks him apart.
I think it is too early for Bane, and I don't think Crock will ever make it onto the silver screen while Nolan helms. Still though, I'd like to see someone of their physical prowess in the next film.