Did someone say "Nickelodeon indoor theme park"!?
I have my own idea for an Avatar land, or at least a potential part of one.
Air Temple of the Avatar (or Avatar Air Temple)
As a part of Avatar Land, the Air Temple would be an ancient home of the extinct Air Nomads, but has since been restored by the Air Acolytes (so it is based circa The Legend of Korra). Thematically, it could be incorporated with Air Temple Island in Republic City. I could imagine there being a huge statue of Aang, though that would probably go against the non-narcissistic way of the Air Nomads. This sort of environment would allow for an immersive world, with the cast members dressed as Air Acolytes, or merchants from around the Four Nations (like the Cabbage Merchant).
The temple would be fully explorable, with several walkthroughs that go up and around the various buildings, towers, and hidden chambers.
Attractions wise, I can imagine the Air Gliders ride from Movie Park Germany could be incorporated. It's basically Astro Orbitor but with Airbender gliders instead of rockets. The second attraction would be a dark ride/simulator on the same level of Shangahi Disneyland's Pirates ride. Sky Bison Spirit Journey (I am hopeless with catchy ride names XD) would take guests through the Air Temple and then through a portal into the spirit world, encountering various spirits and monsters like Koh the Face Stealer, Raava and Vaatu, great dragons, volcanic explosions which are actually the awakening of phoenixes, the Fog of Lost Souls, and even meetings with Uncle Iroh and maybe even Aang's spirit.
Another attraction I imagine is some sort of interactive, physical experience where guests get to learn the ways of airbending, using physical props and special effects to create the illusions, and even bits where they can defy gravity by stepping into areas with huge wind fans in the floors and walls (if you get what I mean). Meet and greets could include characters from both Avatar and Korra.
Other Ideas!
-A Rugrats dark ride taking inspiration from that Baby Herman ride that never surfaced.
-The Wild Thornberrys version of The Jungle Cruise.
-A spooky indoor show based on Are You Afraid Of the Dark?