The original Fantasyland rides in Florida took great liberties with the movies they were based on. The devils in Mr. Toad, Atlantis in 20,000 Leagues, the witch crushing you in the dwarfs' mine etc. were all invented to make the attractions more interesting as ride-through experiences and helped to tell their own stories.
There's a difference between taking inspiration from a movie and being strictly faithful to it.
That's true; a lot of the common early complaints about many of the Fantasyland rides was "where's Snow White?", "where's Mr. Toad?", things along those lines, because people weren't catching on that the idea was that you, the guest, were assuming the role of the films' protagonists. And even then, those rides weren't designed to just be a "book report" version of the films' plots, they were designed around specific moments from the films or a general atmosphere people might have associated with them (keeping in mind that the rides opened in an era before home video releases), such as Snow White's scarier parts, or Toad's madcap style. That began to change in places over the years, like Snow White becoming more of a "book report" ride in its later iteration, but it certainly wasn't the original intention. My point was more that Fantasyland was originally the place with the attractions that were explicitly tied to movies, whereas the other lands avoided that, but the trend of "film property or bust" has made it into Tomorrowland (Stitch, Buzz, Monsters Inc.), Adventureland (Aladdin's carpets, Pirates w/Depp and company), Future World, World Showcase, etc., and it really does have an impact on the overall experience, kind of homogenizing the parks.
As for Flight of Passage, I'm looking forward to giving that a try when I get down to WDW in a couple of weeks, I've heard great things. It sounds like it comes from that older Fantasyland IP tradition: take a concept or an idea from a film and translate it into the medium of a theme park attraction, taking advantage of what the medium has to offer the experience, rather than just passively having guests consume a story or plot recycled from the original film. Doing that can definitely add to the "timeless" element of a ride; if you're not getting bogged down in the film's plot/characters/songs, etc., then the experience can stand on its own feet and thrive independent of the film's cultural relevance.
That said, I still have my doubts about the entire Avatar themed land; I'm sure it looks great, but man, the whole backstory/"lore" they did with it is
really offputting to me.