I'd like to see more of a high tech comic book Batman universe, something that could more easily lend itself to a world where Superman and other characters exist. I hate to bring up the most overrated Batman story arc ever, but the way Batman and Gotham appear in the Hush storyline, I think, could lend itself easily to a movie (though I'm not in any way suggesting they adapt that story because it sucks). Batman is still a hardnosed SOB and the tone is very serious, but the environment is very high tech with a lot of sci-fi elements. Sort of like Iron Man, only darker and more serious. I think that is the way to go.
We've had gothic Batman (Burton), realistic Batman (Nolan) and whimsical acid trip Batman (Schumacher). I'd like to see high-tech, sci-fi Batman because I think it opens the door to Justice League and/or Worlds Finest.