The first time ever I went to Universal is this year. I don't think the whole park is an issue.
There are sections of USF that need help, but that can be said about Disney also. I know there is screen overkill at USF, but Escape from Gringotts used them well. Diagon Alley to me is better than Galaxy's Edge, Toy Story Land and even Pandora in theme. Diagon alley also to me is better than Hogsmeade although Hogsmead is a very good land.
USF is getting more help than you think. Also USF is already have one change. Shrek 4D is gone and is being replaced by something else although I don't know for sure. The replacement is appears to be something minions related.
Also Simpsons theme park rights contract expires in 2028. I think Universal is not going to renewal the rights. I am sure Universal is going to consider stuff for replacing Simpsons once Epic Universe opens. The fact is USF still has a good amount of years left with Simpsons.