I've been critical towards the Pandora world and it not fitting in. I think there is several things that people find difficult to accept with the project. That being said, I do believe the people who worked on this project, at least from what we've seen, have worked very hard on it, and it does look beautiful.
For me, I'm well aware Animal Kingdom was always going to explore the fantastical world of fictional animals, as seen by the dragon being represented on the original logo. Though I wasn't 100% sold on that concept even, I at the very least saw it's potential. Humans have long had beliefs and interactions,and even feelings towards some of these mythic creatures. Right now, there is a mythic animal in Animal Kingdom, being the Yeti, and no one mentions it, in terms of not fitting in, because it does. Man has long searched for the Yeti, or bigfoot. Legendary works of literature have explored animals like dragons, minotaurs, krakens, pegasus, hydras, loch ness monster etc. Many assume that those animals are just called mythic because they are fictional, but it has more to do with the fact those animals are intricate and incredibly important to whole cultures on this planet. During chinese New Years, Dragons are all over the place. Tales of bigfoot are spread throughout wooded areas, loch ness is a tourist attraction. The Sphinx is one of the most recognized images of ancient egypt. These animals don't only represent imagination and adventure, but also the cultures that they became prominent in. For everything Avatar has, I don't think it has that by any means. The sole reason mankind was even on Pandora was to mine it. It had little to do with teh nature or the animals, and had everything to do with the rock found on the planet. Animal Kingdom had the potential to try to make these animals as real as humanly possible, to the point people would question whether or not they were real.
Some on here have compared it to DinoLand. I don't see that at all. Whether you feel Dinoland is good or not, it makes sense that something like that could exist in this magical land, on the outskirts, similarly to Dumbo's Circus situated next to Fantasyland. With the exception of Dumbo and other Disney characters, Dumbo's circus (though I believe it is very well done) has very little to do with fantasy. Dinoland is a way to explore dinosaurs, both with man's interaction with them after the fact, as well as being taken back to the time of the Dinosaurs. Dinosaurs however have had a long standing position in relation to human's interests, understandings and affections towards them. They were real, and mankind has entire occupations devoted to understanding and studying them. They also go out and find them. No movie franchise on earth, including Star Wars and Potter, have had the interest level that dinosaurs have generated over mankind.
Harry Potter over at Islands of Adventure I do feel fits in quite nicely, as originally when Islands of Adventure opened, all the lands were popular IPs, but they also were lands that were based around literature. Marvel (comics), Newspaper comic strips, Jurassic Park (originally a book), Sinbad, Dr Seuss, all can be found in literature, just like Harry Potter is. The icon of Islands of Adventure is the Pharos Lighthouse which is the lighthouse of Alexandria, renowned for it's library. That being said, I think Potter fits in fine.
Pandora, from what I've seen is not a campsite or even a carnival, both things that are unquestionably found throughout the world, but rather it's own planet. A planet that humans can't even breathe on without oxygen masks. In the movie, you don't see human figures walking around Pandora. They have to change into their alien Avatars duplicates on the planet in order to live. The transfer from Discovery island to Pandora will be walking across a bridge?? Unless there's some sort or transporter, or teleportation device, that's going to be hard to justify.
Animal Kingdom is a great park, and Avatar I think honestly takes more abuse then it probably should on these boards. I just don't see the two meshing well. If you were going to take and infuse fiction into animal kingdom, it should be legend and myth, things of yesterday that have aged and grown with us all on this Earth. Science fiction, just doesn't do that. The creatures from Pirates of the Caribbean have more cultural and lasting impact both in legacy, but also being directly attached to mankind. Literally if it wasn't for the rock on Pandora, mankind wouldn't care about Pandora, it'd just be another planet. in the vast galaxy. It's not even part of our solar system. Krakens, dragons, mermaids, and unicorns are fictional beasts made from the minds of man, and influenced throughout this planet. There so old and so storied, few no where the first reference of them came. Every single animal mentioned there has been displayed existing on Earth. They are a part of our history and culture. Avatar is a really popular movie, but it's just a movie. It didn't even produce a comic book or novel series.
One way Avatar will help the park, is at night, as it's glowing forests should be a draw for people who are staying late at the park. Since fireworks can't be exploited, and animals go in after dark, at least many of them do, it is a reasonable advance to come up with things to do at night. I think that is a good idea, though I don't know that a whole land was needed.