Right now there is some pretty major work going on down there, or at least ramping up. RCID does have land allocated for a 5th major theme park in it's current land usage plan.
But with Shanghai opening, AvatarLand, StarWars Land, ToyStory Land and the disney springs work, they is going to pretty much kill the budget. Not to mention, EPCOT needs some love.
Eventually they will have to do something to increase capacity there however. The population is not shrinking!
Orlando Hotel occupancy goes up every year. Eventually Disney is going to need or want more hotels too. Maybe they will complete AoA to their original planned capacity. Maybe a new gate with new hotels.
Does anyone know how the Marvel licensing works? That is a pretty big piece of intellectual property that Disney owns but can not use.
Perhaps Mr. Iger's successor will also have a different long term plan.