I agree with
@Freak that I just don't see Universal replacing our Simpsons with a Pokemon land -- if they do bring Pokemon to the park, they're gonna want space that that spot doesn't have and something like the Transformers plot and the surrounding area does.
That said, my dream, especially after seeing
that scene in
Godzilla v Kong that Adam Wingard even said was directly inspired by Back to the Future: The Ride
-- and I think I've mentioned it before -- would be to see Simpsons replaced with a Godzilla/Kong ride. The "generic street" outside of F&F could lead into a neon-lit city space (let's just say Tokyo-esque) with a Monarch building as the focus, where the ride's story is that we as guests are being invited by Monarch to tour their facilities in the queue and then experience a journey to the Hollow Earth only to get caught up in Godzilla, Kong, and other Titan-related mayhem.
Unlike Pokemon or the Universal Monsters, and just like Skull Island over at IoA, Godzilla/Kong doesn't
need a big, interactive land, and I'd rather see stuff like UM or Pokemon (if they come) be given actual space to work with rather than shoved into the restraints of where Springfield is now. And what would be amazing would be a ride that starts off as if you are in a simulator ride, take the on screen rapid journey to Hollow Earth, and then -- surprise, surprise -- end up in actual sets with props and animatronics complimented by stuff that has to be on a screen (like the monsters fighting). Hell, throw in up close Godzilla and Kong animatronics at the end like RoK for that awesome final punch before we return back to the surface.
As an added bonus, bringing "modern" Kong to the park this way would also allow King Kong 360 to finally go for something else on the Studio Tour, too, all while blending the urban theming of F&F right into it, looking cool as hell at night, and giving the properties with more land opportunities and potential a chance to be developed elsewhere in the park. (Plus, how could would it be to have Kong
and Godzilla involved in park marketing?)