To put it lightly, I'm extremely skeptical that this area is going to be used for park expansion any time in near the future. It's a rather awkward distance from the park and the route is note evenly graded. It'd be downhill going out there, but a rather steep uphill going back. Unless they're going to do a Starway 2.0 or run a shuttle service out there, just the logistics of getting people there and back is a bit of a hassle. It also creates a bottleneck where people going to there have to go through whatever expansion they might put in place in the tram garage/tram load area. Springfield already represents a big bottleneck for the park; having another immediately afterwards is not great planning. Plus, all of those roads have to stay open and accessible for fire and safety reasons, making them much harder to build around.
But the other side of it is that the Falls Lake area is still used by the studio. It's not like a soundstage that can just be torn down and built somewhere else. There's a lot of infrastructure to be able to fill the lake for filming and that makes it much more expensive to try and rebuild elsewhere. Even when they're not filming there, it's a space the studio uses to store a huge portion of their truck fleet, which would have to be relocated if that space went away. I would be very surprised if Universal Creative was looking at that space for expansion any time in the next decade.