I think it's hard to put in a heck of a lot even when gutting the ride totally so in essence I'd imagine it would be easiest to keep it as a sort of theater show in a round about manner. To that end though its pretty tough for me to think of much. In a way tommorland isn't so much tomorrow as we have today but tomorrow as it was seen long long ago. I actually enjoy that though and would keep that sort of theme. It does seem rather short sighted thugh. Everything basically gears towards space and aliens with most rides, apparently that's all our future holds. I kind of liked the timekeeper rides concept, melding history with modern things. It would be interesting to do something with parallel timelines, sort of a back to the futuresque style. In doing that we could keep the theaters and under the ride create various animatronics to rotate and be lifted into where stitch currently sites. Heck even make it more interactive and have a cast member mixed in who could leave that stage and interact with the crowds on various levels.
I dunno I'd just love to see a new take on something, anything, besides more spacemen.