I wonder if part of the challenge when designing areas themed after entire IPs is that a lot of your park-going crowd could have preconceived notions of what would count as "Star Wars" or as "Avatar" or what have you, whereas broader themes (like Adventureland, Future World, Sunset Boulevard, Main Street, etc.) allow the crowd to go in with, potentially, a mind that's already inclined toward being a bit more open. As stated above, Potter was an exception: that world was fully fleshed out in terms of even some of the smallest details, given that you had seven books and a heap of movies largely based around a lot of the same locations. Star Wars offers a challenge in that the worlds themselves are secondary to what happens on them. This can be good for theme park designers, as there are less minute details to have to get just right, or a challenge in that they have to create something that doesn't clash against the audience's preconceived notions.
It's an interesting topic, and I'm sure SWL will be cool, but I do think it's another reason to lean toward more broadly themed park areas.
Let's not go down this road, please.