At WDW, nostalgia is a limiting factor at MK but significantly less so at its other Orlando theme parks.
MK can remain the 'nostalgia park' but the other 3 parks are primed for change.
The front half of Epcot is, after all, Future World. Predictions for the future constantly evolve. Meanwhile, there are gaping holes where additional countries should be slotted into the World Showcase.
DHS's 'Hollywood That Never Was' entrance is a perfect introduction to today's Hollywood. The back half of DHS is ideally suited to highlight the latest in film and tv.
DAK is so new that it does not have a nostalgia factor. It can evolve as appropriate. Certainly, nostalgia did not stop Disney from adding Pandora.
Those within corporate Disney who use nostalgia as a defense really use it as an excuse to avoid further investment in WDW.
Disney repurchased
$12B in company stock over the last 3 years. You'd think they could spare a few billion to fix WDW.