I'm glad we're getting Epic Universe, but I think it's perfectly valid to prefer IOA and USF (especially USF...) were made as good and fleshed-out as they could possibly be before entertaining the idea of another gate. I'm sympathetic to that idea, as the board's resident "Nintendo should have still gone into KidZone" advocate.
There are some people out there who argue that Disney-MGM Studios and (especially) Animal Kingdom should not have been built when they were (if at all); I think that's a crazy position, and I would not want to lose either of those parks, but I understand the theoretical logic that their expense prevented some of the existing parks from reaching more full maturation.