Avatar is a huge mistake on many levels. The reason outside franchises have worked in Disney is because it matches a fun sense of adventure. Indy and Star Wars have their dark moments, but they*remain*light hearted. Avatar doesn't share that tone. Its mood is not that of Disney.
Its also a huge mistake to think Avatar is a top tier franchise. As others have pointed out, its ticket sales were not that impressive. Box office? Yes, but as they said, 3D ticket prices are responsible for that. Even if it really did have the best attendance of all time, though, that doesn't mean everybody enjoyed it. There are a lot of people who despise the movie, and even those that do like it, don't really love it.*
There is a positive in all this, but in my opinion it has little to do with Avatar. No doubt, the imagineers will come up with some kind of spectacle of an attraction that will amaze guests and be some what good for attendance. But its only the Avatar name and stakes to compete with Potter that will give them the*confidence*and*pressure*to do so. I guess what I am saying is, if they put this much on the*shoulders*of an original concept, given it the same budget, and completely executed it the way they promise to execute this, we would have something more rewarding, and*likely*more*successful.*