EPCOT is a VERY emotional topic for me.
As the son of a CM, we used to go to WDW a LOT when I was younger, and as much fun as the MK was, EPCOT Center (as it was called back then) was my favorite park.
Even though I still enjoy Epcot today, it can't hold a candle to the awe-inspiring park that it was for so many of those years when I went to it so often in its original form.
Horizons, the original SSE, the original UoE, WoM, the original Imagination...I miss them all dearly and often find myself watching YT videos of those attractions and/or listen to old ridethrough audio recordings.
However, when I really think about it, what I miss most about Epcot isn't just the physical attractions--what I miss is the idealistic, positive, sincere way in which EPCOT presented ideas back then. I found the original EPCOT to be a wonderful, visionary park that took a serious approach to ideas but still had just enough quirky humor to keep it from feeling too heavy-handed. In this respect it was the perfect balance in mood and setting for the kind of park it was meant to be.
While I realize that the original attractions and physical properties of the park would feel somewhat dated these days, I am disappointed in how the park has changed from something with idealism, vision and edutainment and has been turned into something sillier, less refined, and more about entertainment. The way the ideas of the park are presented IS something that didn't have to change and newer attractions could have kept that more serious tone and created a sense of awe without bringing in characters, more thrill-like rides and such. We already have other parks for those kinds of attractions.
I could sit here all day and ask for all of the original attractions of Epcot to be brought back (including the original look of The Land pavillion interior), but that simply isn't realistic. But what IS possible is to get the park back to a forward-thinking park that is awe-inspiring both in the scale of its thinking, ideas and attractions and to keep the branding of the characters and such to a minimum. So if there was something I could change, it would be to return the mood, atmosphere and the more sophisticated yet inspiring way in which the original EPCOT presented itself.
The setting and mood of the original El Rio del Tiempo vs. the current Gran Fiesta Tour is a perfect example of the kinds of changes I hate to see at Epcot because it took something that was trying to present itself as authentic, educational and cultural and made it silly/fun. I'm not saying that I don't like Gran Fiesta in its own way, but it pales in comparison to the emotional, atmospheric impact of the original, which is how I feel about much of Epcot these days.
All, just in my humble opinion of course.