I have no issues with thrill rides at EPCOT so long as they are in the spirit of the original vision of EPCOT. I think Test Track 1.0 was a great example of how a thrilling ride can be incorporated appropriately into EPCOT. Your example of appropriate coasters being themed to corresponding mountains in World Showcase is another fair example. I am just not a fan of adding thrill rides just to appease people looking for thrill rides (as seems was the case for GotG).
In the same breath though, they need to be careful removing too many minimal/no height requirement attractions and replacing them with thrilling rides. Kitchen Caberet, World of Motion, Horizons, Universe of Energy all were attractions that literally anyone could go on that were replaced with attractions with height requirements that exclude a fair number of guests. In exchange, we got Remy and Moana as two attractions with no height limits. They really need that Mary Poppins attraction and something in WoL to bring back the same number of attractions for the real little kids before they start talking about adding more thrilling rides IMHO.