A lot of people don't actually know what they want. That's why we get crap like Avenger's Campus, because people just think "buh buh hurr durr it'd be like cool to have a Super Hero Land & Stuff, I definitely won't get sick of Marvel after 30 movies and 20 TV Shows, let's build a land because Spider-Man is cool!!!111"-and are then surprised it sucks because "Character I like" and "interesting environment" aren't 1:1 all the time.
A Pandora land, or even just a Pandora ride, is way more likely to be actually interesting than things that are thrown around all the time like Monstropolis, Frozen, etc. There's a reason Pandora works like gangbusters in Florida and is reportedly the number one theme park land at WDW at least, according to TouringPlans. Compelling environment=compelling land; compelling environment=a lot of work is done for you.
To me, there is a dearth of surprises in the world more generally, but particularly in theme parks as of late. If we must play in an IP-only sandbox, Avatar is far more likely to actually surprise in a positive way than pretty much anything else they could build IMO.
And I don't care what Brickey thinks, he annoys me. He also had the audacity to say Hollywood Studios was the worst designed Disney park when he's almost certainly been to the crapshow that is the Paris second gate.