If Lion King isn't appropriate for the park, than there are very few IPs that would work for the park. The fact that it's been in the park since inception already contradicts this opinion.
Joe Rohde has been consistent on his themes of the park:
- The intrinsic and superior value of nature (An overgrown temple with animals residing inside exemplifies this without outwardly stating it)
- Personal Call to Action (all this has to be is a parting message at the end of the ride)
- Transformation through adventure (this is probably the most generic of the themes)
One of the signature songs from the Lion King is the Circle of Life. It's an underlying theme of the movie. Now, does Festival of the Lion King hit that message home particularly hard? No, not really. To that I say, "Yeah, but still."