Can I lodge a complete disagreement?
Your criteria above describes the Avatar movie far more than it does fantasy myths. Despite the mental math afterward. That's literally the moral of the movie's story: Coexistence and respect for nature.
I know there is a strong romanticization of the Beastley Kingdomme concept, but what they had envisioned was inferior to what they are building for Pandora. Just because something lacks an IP association or was dreamed up well over a decade ago does not always mean the product would have been better. The opposite applies of course, often they phone it in by attaching an IP and calling it good enough.
Arguably we can look at the list of the best rides in the world. Some are IP based, some are based on long decayed IP and some are completely new creations. We can also apply it to some of the worst rides we've seen produced and all equally apply. It's the execution that matters far more than the starting point.
We think too fondly about the what if's. Beastly Kingdomme could have been ok, but not the second coming simply because it was a 'new' idea.
On another note, I don't think Beastly Kingdomme is a far-flung impossibility either. Personally I'd rather see South America before AK's Fantasyland. But there is more than enough space.