As guests, I think there are many of us who would prefer Disney's Animal Kingdom to be about the animals on the continents of Earth and how human cultures respect those animals... not about the CGI creatures, CGI humanoids, and CGI landscape of James Cameron's imaginary Pandora.
But for The Walt Disney Compnay, It's not about having the best, most thematically cohesive theme park. It's about leveraging the successful Avatar brand.
Bob Iger saw the money that Avatar took in at the box office, and now hopes that guests will flock to Disney's Animal Kingdom with their wallets. Let's call it "learning from the success of Universal's Harry Potter."