That's a good point. What about a movie in the world of Inception, with new characters?
That could be cool. That's pretty much what I was thinking of.
Of course, it could be risky, but I think it'd be better than bringing back everyone.
OR... have a couple of characters return (Arthur & Ariadne, OR Saito, maybe Eames, etc.). But it should have a different feel than the first movie. And, without Mal screwing things up, there would have to be something else going on...
Or just screw it and make the sequel a Goldeneye-like video game instead.