Gonna throw out another concept/idea I've been thinking about: does anyone remember the early concept for IOA being "Cartoon World," which would have just focused on DC Comics, Looney Tunes, and Seuss? While obviously I think doing a park based on that narrow of a range of IP would be a bad idea, it does make me think. What if for Gate 3, instead of having 6-7 smaller lands, there's only 4 or so? And they could each be larger, feature more subsections and such, and be WWoHP-level immersive. Basically IoA on steroids.
I think Nintendo and DreamWorks can already do that; Both have a huge amount of IPs that could mix together fairly well in huge, family friendly lands. Other IPs that could work for this treatment are Jurassic World (imagine a true recreation of the park, featuring a huge scale and a large amount of attractions rather than the simple one we have now), and Middle-Earth (if they can get the rights somehow, this IP would truly deserve a huge land).
What does everyone else think of this idea? I think WWoHP being split across parks is a very special and interesting thing, but I personally would love to see what UC could do if they essentially built the Diagon and Hogsmeade-esque lands together in one huge, immersive environment.