Simpsons is going to have to be removed. I've seen some people throw out wishful fantasies that Disney doesn't care about simpsons, Simpsons wouldn't work in a Dsney park, letting Universal keep Simpsons makes Disney money, maybe Disney can let Universal keep Simpsons in exchange for the marvel rights back. But it's not happening. Universal has the lock on Marvel rights outside of GoTG in Orlando and they will never give them up, especially not for Simpsons. Disney is not going to just let Universal keep Simpsons regardless of their own plans for it or how little money it brings them currently when they can hurt Universal by forcing them to have to remove it.
Besides, losing Simpsons isn't going to be to big of a hit for Universal. It's mostly a glorified food court, one flat ride and a screen based dark ride.
The question is what Universal replaces Simpsons with? Once again there are delusional people suggesting they bring Back the Future back, but that's not happening people.
What can they replace Simpsons with? Pokemon was supposed to replace Kids Zone and Zelda was suppose to replace Lost continent. Maybe one of those gets moved into Simpsons place and either Kids Zone or Lost Continent get a stay of execution? Or something else?