Obviously this isn't going to be in the third park, but i'd love to have a park dedicated to b-movies that have gained cult followings. Something like a Tarantino-dream park.
In the park I'd love to see a whole Manhattan-jail themed land themed after "Escape from New York". Here the main ride could be in the style of Spiderman, where a taxi ride takes you through a distraught Manhattan, full of maniacs, etc in order to find the kidnapped president. Another ride could be themed to Maniac Cop, Cloverfield, or any other b-picture that takes place in New York.
I'd also like to see a land dedicated to cult horror. In this land we could see rides such as Killer Klowns from Outer Space, and the story could have us saving our tour guide from the clowns after he/she is taken captive in a balloon. Then we could have a horror makeup show, or a classic monster haunted house.
I'd also like to see a land themed to disaster films, which is kind of what Disaster was, but here we'd see a Speed ride, A ride themed to the Towering Inferno, Dante's Peak. Just a land dedicated to the disaster cinema boom that happened both in the 70's and 90's.
I have yet to think about what else this park could offer, but I think it would be really cool to see a park dedicated to cheesy movies. I don't think it will happen because the general public wouldn't eat up something like this, and also because Universal probably would have a hard time finding the rights to all these films, and there is no desire this will ever happen. This is just my dream for the 3rd park, a dream that I'm aware will never happen, but something I fantasize with