So here's a list of possibilities of a 4th 'dry' park Universal would be interested in.
First of all, I don't think Universal would do this unless they receive half the profits, which I still think this is not a possibility because Comcast wants all the $$$.
-Warner Bros: They have a strong relationship and I can see this be an indoor park that's very immersive, possibly a 'deluxe' experience. (Imagine, Uni can have BOTH Marvel and DC.)
-Ferrari World: It seems to be a hit in Spain and Dubai, so why not try it out here? I see it being a very small park with 2 coasters at most, a few race tracks (take Fun Spot out of business, RIP) and some flats.
-Nickelodeon: Indoor park, but more themed than the park at the mall.
In summary, I only see a non-Universal branded park at this site to be indoor. very small and a premium experience.
This doesn't have to do with a dry park but you would think that maybe Uni can lease space to have an Atlantis Water Park & Hotel?