The problem with Beastly Kingdom is it doesn't have that magic "S": Synergy
It seems clear that Disney was hoping Avatar would bring in "new business"...customers who aren't part of the traditional WDW audience but would take notice of Avatar and/or James Cameron.
That's what Universal got from Harry Potter. The Mummy, The Simpsons, Men in Black, Dr Seuss, Shrek, Spider-Man and many more properties were not enough to get certain people into their parks, but WWoHP was the proverbial tipping point. Millions of new customers responded by opening their wallets.
Beastly Kingdom may have turned out to be a fantastic addition but without any sort of name recognition, it's probably not enough to draw in millions of first-time guests who wouldn't otherwise visit WDW. That's the end result of the economically competitive / social media / smartphone / short attention span society we live in today. Sometimes just being "good" (excellent, superior) isn't good enough.
Personally I've never even watched Avatar. But I was in favor of that project because (IMO) the potential upside warrants a significant investment on Disney's part and Cameron's involvement would all but guarantee high quality. If it's good entertainment, the theme becomes secondary. Even non-fans could still enjoy the experience. Don't think I have ever seen "Song of the South" or "Ichabod and Mr Toad" but Splash Mountain and Mr. Toad's Wild Ride are still worthwhile.
Now if the rumors are to be believed, Disney may be hoping a carbon copy Cars Land provides the synergy and attendance bump they are seeking. Yay....more ride clones.
