If you're going to be concerned about too many characters, the Avengers has to jump to the top of that list by default. There's going to be a long list of star power in that one. If they can balance out all those characters, more power to them.
Nolan's already put together some good balance in the first two movies. Ra's, Scarecrow, Falcone, Batman, Gordon, Alfred, Fox in Begins and then Joker, Dent, Maroni, brief Scarecrow appearance, other mob members, Batman, Gordon, Fox in The Dark Knight. That's a pretty long list there, pretty similar in length to what you listed for the new one. I also don't think they wind up going with the rumored Talia Al Ghul character like you mentioned.