My opinion: give it time. We've waited this long, so why throw in the towel, now? The fact that they showed that Nicholson Joker means that they're not done with Burton's Batman just yet, and that might even be the primer for a Returns reveal. They've got a hell of a lot of Batman on their plate, and there's no way in hell they're going to turn down that kind of cash flow. Marvel had their time with Avengers and Iron Man, and things are slowing down there, so, I actually agree with Nova's prediction from the Arkham City thread. That prediction being that we're going to be seeing a **** ton of Batman in the near future.
They've now got three different lines on their plate, four if you include TDKR, which, from the backstage stuff, it appears they aren't done with. I'm just awaiting the glorious day when we see Arkham City, Returns, 66 Batman, and TDKR back to back to back to back.