I agree with what you're staying to an extent -- I think the fact that Xandar is another planet with an alien species (even though they are indistinguishable from humans) is the aspect that would be most incongruous with classic EPCOT in that scenario. If you removed the Guardians and Eson and had the ride itself just be a journey through space, then replaced Xandar with some sort of fake future scientific organization from Earth, it would probably work better.
God if ONLY we could have had that... hell they could have changed engery's pre-show to make some reference to the Guardians.
Picture this, you enter the "then" current pre-show, at some point, that signal fades out and a signal transmission takes place.
The Guardians break in with some kinda nonsense the world is about to end, climate change, yadda ydaa.
Then they say something like, "lets take YOU back in time, to see why moving forward with a greener energy is the right thing to do"
You enter to the "old" load area, but revised of course as you get into the roller coster cars instead of the theater cars.
The room goes dark, and BANG, back you go thru the Dino's, then out to the new show (err, I mean screen filed building with plenty of CGI FUN!) and then into, theater 3 (the old unload) which could easily go something like this: The lights come up and the "CLASSIC" old energy "feel the flow" starts playing... your coaster car then slowly rolls to the proper unload area of the station and exit out.
Okay rough draft, but Jesus how hard is that to think up?
I mean, hell it would save a ton of money too, you don't really need to do much work to existing ride space
(think when they put mummy into the old kong building at U/O)
It's almost like, with this project the mantra was, "how do we RIP OUT EVERYTHING HA HA HAA and shove it in there face that we DID RIP IT OUT HA HA HA.... Oh and if that is not enough lets insert a throw away line {See the veggie fruit fruit} which is so out of place, we will MOCK THEM EVEN MORE, those old Epcot Purest's.. HA HA HAA" (insert Zach evil grin)