While Pandora is my favorite section of any of the Disney Parks (it's just stunningly beautiful, especially at night) the biggest flaw of the land is the lack of Na'vi. It creates this feeling like the Na'vi have been wiped out or something.
I think the problem is that James Cameron wants the Na'vi to be realistic, but there is no way a human in a costume could realistically look like a Na'vi. They are 10 feet tall! So the next solution is having animatronics. But the problem is animatronics are 1. Expensive 2. hard to control in a "meet and greet" type of atmosphere. If James Cameron and the Disney Imagineers can find some way to have meet and greet opportunities with realistic-looking Na'vi animatronics (who can somehow interact with people), they will have perfected the land of Pandora.