This is the reason why I don't think this was the best idea they could of chosen. Just because a film has huge box-office numbers doesn't mean that it has a huge following. Just look at Star Trek, it has small comparative box-office figures yet has one of the biggest and most dedicated fanbases of any franchise. Avatar hardly has a large fan base. Most people who saw it were thinking more of the technology that went into making it as nothing else was like it. It was rare that people go, "Avatar has the best story and I can't wait for the blu-ray release so I can watch it again and again". It is basically a movie that in a few decades it will just look stupid, as the focus of the movie was in how it looks, but in the future when everything has improved. Even now you can see the change in the realism since the early 90s. So by building a whole land on the movie will be horrible in a decades time since it will be of a movie which most people have very little interest in.