As for Walt's original vision of Tomorrowland, I don't think we've seen it for over 30 years, so really at this point anything goes. A full-on return to the whiz-bang future wrapped in a corporate World's Fair would not only fall totally flat on a jaded modern (post-post-modern?) audience, but the capital improvements made to Tomorrowland over the last 30 years (and more importantly the most recent decade) pretty much guarantee that not only will we not see the cohesive "lived in city of the future" theme that MG longs for, but I can't imagine seeing anything more than another half-baked overlay of some sort. Star Tours might get a new film (hooray... and you can bet it will be breahlessly sold like T2 3D was - as the most expensive film per-minute ever made), Space Mountain obviously won't be torn down, and just got a make-over that was anything but awe-inspiring, Buzz is essentially brand new, a graduate level lecture on particle physics would be an improvement over HISTA, and surely that will remain a theater of some sort, the Peoplemover track is wrecked, and everyone knows Nemo and Autopia aren't going anywhere any time soon. I see very few viable options for a revitalization of Tomorrowland. A DCA-styled makeover is extremely unlikely.
If you want to see the future, read Wired magazine, go to a Home Show or the CES.