Since this is about speculation, I will throw in a few more ideas that might not be on the radar anywhere, but I am wondering if any of these could be feasible in the future (potentially in any park):
1. Game of Thrones: Incredibly popular TV show, distinct themes, many options for rides, and they are still doing spin-offs etc. Obviously another IP that would need to be licensed, but I think as a land it would be a great option. Personally I have not watched the show, so I won't be able to give any specific ride ideas, but I am sure there are plenty.
2. IT: Now obviously this would be a land that would not be suitable for little kids, which makes it a long shot, but as far as horror goes, IT is as mainstream as it gets. The movies were popular, and the TV show that started recently already has been locked in for 3 full seasons. There is plenty of lore, iconic locations that would make great themed lands and lots of options for ride ideas. But also would need to get fully licensed.
3. A music based land: This would be something that has not been done before, and likely would only be a small land and require a lot of licensing. Think "Great Movie Ride" but for music, going through different scenes of different artists. Might not be my cup of tea but I think people would go absolutely crazy vibing with a Taylor Swift animatronic or a rocking to ACDC. Due to licensing issues this might be the most unlikely though.
Again, I know this is not specific to rumors, but just general speculation if concepts like these would work.