As trite as it is, if UOE truly does become a roller coaster, that's one more thing at WDW that everyone can do that's lost. I have inner-ear problems, and one of WDW's main draws for me is the elaborate theming and the dark rides; I can't do coasters. When we went to WDW as a family when I was a kid (80s and 90s), everyone from my 91 year- old grandfather to my 3-year old cousin could enjoy them together.
Yes, universe of energy is tired and far too long for the content, but as a woman without children who enjoys seeing characters out and about in the parks but has no desire to wait in line, I love Epcot for the lack of coasters and the shadow of former glory/theming. As prices rise and more dark rides are replaced with thrill rides or meet and greets, I spend more vacation time and dollars elsewhere. If I really wanted a concentration of thrill rides, I could go elsewhere - closer - for much cheaper.