I think compared to back in the day it is losing an identity. No doubt. I remember it in the 1990s and ironically I didn't like it all that much. I was 14-15 the first time I saw it, it is quite possible I just didn't appreciate it until I grew up. I felt the same way about the Baseball Hall of Fame in Cooperstown when I was 13.Full disclosure, I'm not quite sure what side of the discussion you're on. As has been said in other replies even the Epcot of 1982 has nothing to do with Walt Disney, the man himself, and his vision. I'm sure he'd have had a line about the park never being completed and always evolving, etc., and that's fine. There's just no original stories or original rides anymore. I'm thrilled that your son likes the modern version of Epcot, I don't take anything away from people that enjoy the park in its current form. Everyone's different. Somewhere along the way in the late 90s, budgets were cut and things went off track, and I don't know what Epcot is anymore.
Epcot will never be the Epcot of the 80s and 90s again, because that doesn't sell tickets (and apparently didn't sell tickets to the company's satisfaction even in the 80s and 90s). There's been implications that the lukewarm response to Rivers of Light (a nighttime show with no Intellectual Property/characters attached) is what forced characters into the future Epcot nighttime show. They have to leverage this IP that they've spent billions on.
Future World has just been suffering for years with old, outdated, uninspiring attractions and it's frustrating because it used to be the most cohesively themed land in WDW. There's very little to distinguish Epcot and DHS from MK anymore. I recognize that doesn't bother everyone, and that's OK too; theme parks are meant to be enjoyed for what they are. It would've made plenty of sense to keep the "classic" Disney characters in MK, make DHS a "ride the movies" hyper-modern park (dump all the Marvel stuff there, Star Wars, hell, tell me Tron wouldn't have made just as much sense in Hollywood Studios) and keep Epcot as the Science, Discovery and World Cultures park. Once upon a time it felt like Disney cared about the park having an identity.
That being said, to this day, in its current form, is there any other place that is close to being similar as Epcot? If you saw it for the first time what would you compare it to? I can't think of anything.
Sometimes I think we have to look at the park through a first-timer's eyes too. My cousin came with us on our last trip. Never been to WDW but is a Disneyland veteran. He loved WDW and quite frankly loved Epcot as much as anything. He just loved wandering around the countries and getting a feel for it. Or seeing things that are still pretty unique outside of Epcot. American Adventure to this day is still very unique. He loved the balance that Epcot had. Maybe he liked MK better, I am not sure, but he loved Epcot.