In theory this is great to hear.
A single large-scale project probably isn't what's needed though. More accurately, each park needs additions or updates.
MK - While the park needs capacity, it could also stand to see some classics get some updates (Space, Peter Pan). I've long voiced my opinion on stuff that should be relocated or removed (it's a small world, Carousel of Progress and the Speedway), but I believe the easiest / least intrusive area to add capacity would be Adventureland unless someone else has another idea.
EPCOT - Desperately needs ride updates. It's received a couple of additions in recent years. Imagination has neededan update for 20 years at this point, nearly everything else in that park outside of Cosmic Rewind, The Land Pavilion, Ratatouille and Frozen need updates. Editor's Note: Don't view this as an endorsement of Frozen in EPCOT.
DHS - The park needs ride capacity. It also wouldn't hurt if every show in the park outside of Fantasmic was updated or replaced.
DAK - The park also needs significant ride capacity.
Epic Universe is expected to have a dozen+ rides. There's no reason Disney can't build or replace 2-3 attractions per park over the next 5 years. They won't, but they need to.