Bane would be a huge mistake. He is far to unrealistic (yeah I know its a movie and its based on a comic book) to fit into the current Bat universe movies. They need to stick to non powered vilains like Penguin, Riddler, Catwoman and Calendarman.
The one thing they need to avoid from the previous Bat films (and last Spidey film) is adding too many villains/characters. Two per movie is fine, but anything more is overkill.
Oh and if they did bring back Rachel Dawes as Catwoman, that would be one huge pile of arse! I am glad she is dead, as she is the one part of both films that I hated. Her character was just so fucking annoying!