Looking at Splash Mountain just from the fact that those who know the story are getting fewer and fewer it needs to be changed to some other theme. I am in my late 40s and I remember watching Song of the South on TV (we had 3 channels so it wasn't on cable) when I was around 7 or 8 years old. If you figure that the odds of anyone under age 40 having seen Song of the South (yes I know you can find bootleg copies online all the time) from a legitimate source that a link will remain stable is low.
https://www.census.gov/prod/cen2010/briefs/c2010br-03.pdf
Using the 2010 percentage of the US population by age groups and further making an assumption that the 25-44 year old group is spread equally across all the age groups making each age in that group 1.4% of the population multiplied by 5 years (40, 41, 42, 43, 44) and then adding that number to the 45-64 age group and the 65 and older age group results in 46.4% of the population being in an age demographic that they might have seen it at some point before Disney pulled the movie.
Going off the 46% of adults in the US have seen a movie in a theater in the past 12 months according to this site
https://www.statista.com/statistics...=During a survey in June,once or year or less.
aproximately 21.344% of the population has seen Song of the South in a theater rounding it up to 35% to account for those who have also seen it on video and you still have 65% of the population that has not seen this show. As those in the 65 and older age group reach the end of their lives and pass away this number is only going to grow.
So the next question is what to change the theme to keeping in mind that there is water flowing in the ride. So what familiar Disney Movies have a significant amount of water in theme that there is not already an attraction.
Leo and Stitch-but that is more of an ocean and not along a stream, creek (not a creek too slow moving for that), a river is more appropriate.
The Princess and the Frog-has water and is at the appropriate sizing for the type of water
Tangled-again has water and is appropriate but having a dramatic drop is not the best for a your floating along watching the beautiful floating laterns to end with so eliminate that idea.
Moana again more of an ocean type story.
Jungle Book-appropriate water sizing and speed of the water moving but there is already Jungle Cruise and does a Jungle book themed attraction belong more appropriately in Animal Kingdom and not Magic Kingdom. In my opinion yes.
This brings us back to The Princess and The Frog as a theming suggestion to change Splash Mountain too in the near future (please do not start any more construction until the ones that are ongoing are complete or if it can not be completed in time for the 50th anniversary of Magic Kingdom) so Splash Mountain Theming at both Magic Kingdom and
Disneyland should be changed to a Princess and the Frog Theming.