This is the real problem.
Pandora is so successful because the IP is basically irrelevant. You don't need to care about Avatar (or even have seen it -- I never have) to enjoy the land and the rides because they're designed incredibly well and don't use the IP as a crutch. That hasn't been the case for a lot of other recent Disney builds. Smuggler's Run only really works because you're flying the Millennium Falcon; it's not a very good ride on its own. Frozen Ever After is completely reliant on the Frozen IP and would be one of the worst rides in the parks if the Frozen characters/songs were replaced with something generic (to be fair, that's true of a lot of C ticket level dark rides, although I'd argue FEA's overall execution is worse). All of Toy Story Land has this issue. I'm not going to break down every example, but it's relatively widespread
I think it's much easier to build a great attraction without IP than it is to build one with IP. It's not that it can't be done -- its that it's easy/tempting to use the IP to prop up the ride, cut corners, and cover up flaws in a way that can't be done without that IP love/familiarity.