So it may not be the last one in the current set *if* Nolan changes his mind. At least he's got Inception's success to help him do what he wants on the third one.
You know what would be cool? There's so much room for "canon fodder" in these superhero films that. They could work in a Batgirl into the next film and it'd be kinda cool if it turned out to be Katie Holmes.
as far as villains go... I was disappointed to hear that it wasn't going to be the Riddler. Black Mask would make sense given that Catwoman is in this one. Bane would be another good choice.
Hell... in video games, not even disembodied heads prevents people from coming back to life. Like in WoW... dragons that were killed and their heads displayed made a comeback in this latest expansion. /facepalm