Well, specifically, Disney was unhappy with the idea of hundreds of Segways being littered about in front of their attractions.
They love the technology, but they don't want to increase the problem they're already having with strollers - they take up space, create traffic jams, and are just plain ugly. Segways definitely wouldn't be a benefit there.
What I'd love to see is a combination of Segway technology and the GPS based system in use in Tokyo for Winnie the Pooh's Hunny Hunt and the Aquatopia. That would be amazing stuff. Segways that weeble and wobble, but don't fall over, and they can be free roaming, too. . .
I don't know much about the Mission: Space ride system, except that it uses two centrifuges with, I think, 4 pods apiece. They're coming from a military contractor in upstate NY, I think. I could be totally off about the location, though.
The plan, I think, is to simulate launch with the centrifuges. . . and slowly decelerate them within in a certain relationship with the body's inertia to induce a weightless sensation. It seems a bit odd, and it's hard to explain, but it may yet work
...and for what it's worth, the guy I'd spoken to is no longer with WDI. I've met lots of cool people after they'd left, though. . . I even know the guy who's responsible for the outdoor lighting package on the Twilight Zone: Tower of Terror. Now he does commercial and photographic lighting outside of Chicago.