In my opinion, while it is cool that Rocksteady is still making Batman games. It has gotten rather dull with them.
*SPOILERS FOR THE ARKHAM GAMES*
I just hate the fact that the Joker is STILL the main bad guy from the looks of things, Batman has a pretty damn huge rogue gallery, so why just stick to ONE VILLAIN?
I just hope the rumors are false, seeing how the Arkham universe is better left alone since it is damn realistic. Sure, cameos won't hurt, but having the Justice League would make the game a bit ridiculous.
Yes, I think there is a reference in Arkham City, where one thug says "that freak in Metropolis" and obviously Superman is the "freak" there.
But seriously, they need to lay off the Joker, sure, I like the villain, I like Mark Hamill's interpretation of him in the cartoon and games (although John DiMaggio is my favorite Joker), but we need more than just Joker centered games. Might as well call the series "Batman: The Joker's (subtitle)" as a whole.
Rocksteady feels like a one-trick pony now.