I also don't think "The Dark Knight Returns" will be the next title. I believe they'll use something completely different just like TDK is different from the first film. I like "The Caped Crusader" and "Avenger of the Night."
I agree with Sam. I don't want this Batman series to go down the "guest star of the week" road. They don't need to start hiring a name, just continue hiring the best actor for the role. If that happens to be a big name star, so be it but, don't chose the actor just because they have a big name.