I think that something to take away from this Epcot refurbishment is as follows: The name stands for Experimental Prototype Community of Tomorrow. To me, this means that currently, the park is in shambles of what Imagineers thought a futuristic community would look like in the 80's. However, time has finally caught up with Epcot, making things like traveling; whether by spacecraft, by car, or by parasail, a thing of the past. Yes these rides are all thrilling, however they lack that vision of futurism and possibility the park was intended to have. At one point the park did have that spark to it, but it's become outdated; much like our TL in MK.
I think that, given Disney does this right, Epcot will have the same theme as it was originally intended to, an Experimental Prototype Community of what Disney hopes our future could possibly be from a 21st century standpoint, not a 20th century one.
From the Blue Sky artwork I can tell that while some of our favorites will be getting changes, they intend on emphasizing the idea of the future. Isn't that key to have a Future World?
With this new Future World in mine, GotG fits perfectly in my opinion because they showcase a ton of alien races, all living together in one way or another; that's a thing of the future. I think that in this new Epcot, Disney is going to try to showcase all the different possibilities of our future rather than a single generalized view distributed throughout the park. Now, what they plan on doing to the rest of the rides in Future World is unclear to me. But I think we need to trust Disney in their decision making process.
Besides, they've been building theme parks since the 1950's; in that time, so many attractions that were once beloved by so many have been re-themed and replaced by the attractions that we all know and love today. I think that they know what they're doing by now; if they didn't then why would all of us have such fond memories of going to the parks?