^Exactly. I don't think it's obscure in the least, just watch the Ghibli section in Japan light up with conversation about their films next time you are there. They're much better at what Disney and Pixar animated films do best (Let alone good friends with Pixar, business relations with Disney) so there's no question about fitting in. And Disney could use the less jarring and visually stunning original rides that could be built around almost any of these movies. There are only two problems:
1. A good deal of Americans won't watch the same show/film they'd adore if it was live action and on HBO if it just happens to be Animated and from Japan. Basically the same people who woot around World Showcase for "Ferr'ign beers"
2. Ghibli HAS already dabbled in the Theme Park business with it's own "Ghibli Museum", which is strictly designed and carefully restricted to be an intimate and personal experience, with no lines or unsightly infrastructure. It's all just stunning and magical in a way I imagine no Theme Park could be on the large scale it takes to be a theme park.
So basically this is one of those things they should, by all accounts, BE doing-but never will.
Fun Fact: The Toy Story Zoetrope in DCA's Animation building has a placard noting it's thanks to the Ghibli museum's 3D zoetrope which inspired it.