Well, I can't speak for anyone else, but I can honestly say that it wouldn't be worth it, imho, to connect Nolan's world with the JLA one. One of the reasons why Nolan's world worked imho, because it was based on the idea that Batman was the ONLY hero in his world and that it was one without any super powers running about.
The Dark Knight Rises was meant to serve as a conclusion that "world" imho; there's no need to resurrect it and risk potentially tarnishing it as well.
People have been waiting to see Superman and Batman meet for a long time on the big screen, but I think it's only been based on the notion that it'd be Clark Kent/Superman and Bruce Wayne/Batman. I mean, how would people feel if it was Superboy that was meeting Bruce Wayne instead of the original Superman?