That is not really a fair comparison...now if Simba had an actual ride that taught you about conservation with beautiful sets and animatronics, i think it WOULD be as popular as Frozenstrum... but to just put together a film with characters and say , see Edutainment doesn't work, is not really accurate...
Agreed, but if the trend is to use IPs, then using them in a new and clever way makes far more sense than just rehashing the movie ala Nemo, Little Mermaid, etc . . . For example, there is no Beauty and the Beast attraction at Walt Disney World, but the Gaston Tavern and Beast Restaurant are nice additions. In part, this is because they are eateries, and not just rehashes of the story. The movie wasn't retold, it was plussed. Splash Mountain works in part because it is both animatronically amazing and is a thrill ride. Effects wise, the new Arial ride is impressive, but the storyline is not unique enough to grab you. In my opinion, it's a disappointment.
What works is going beyond the basic movie. When they just rehash the movie, it's unsatisfying. When they rehash the movie in a very cool way like Splash Mountain, it works. When they simply throw a façade of characters onto something that in and of itself could already be cool, like they did with 3 Cabelleros, it disappoints.
Similarly, the Imagineers could make Guardians somehow fit into the larger and grander theme of Epcot. If they just rehash the story or conjure up new villains, it will definitely be disappointing at some deeper level. It also won't fit the overall theme of Future World. Something better can be done to make the story unique. They just have to have the willpower to do it and not take the "safe" route of rehashing the movie. It worked with both the old and new Star Tours, and it can work here as well.