Avengers is just over ONE-THIRD of the way to matching Avatar, maybe coming up on halfway in a week or so. Still a LONG way to go and their bell curve of earnings is dropping off rapidly (still an awesome movie though!).
I'm excited for this, Cameron has already demonstrated that he can collaborate to make an exciting attraction (anyone remember Terminator 3D?). I just hope the park is designed and budgeted so that it remains in good shape for years to come.
No matter what the theming is I think it will be packed for several years until the novelty wears off (and according to WDW statistics, for 70% of the guests EVERYTHING is a novelty as they are first [and only] timers). Who really cares if it is dinosaurs, Na'avi, or Grimm fairy tales? An exciting ride is an exciting ride, I consider the themeing to be icing on a delicious cake.