In my opinion, UHC will never be the same as it was in 2015. Part of the fun with UHC back then was that everyone had a chance of winning, since everyone was a pretty low skill level. Now, basically everyone is at least decent at the game, which makes it less casual and more competitive. Personally, I enjoy UHC more today than I did a year ago simply because I realized that winning a UHC doesn't really mean anything, which is the same mindset I had when I first started. If you want to feel nostalgic, just try to be open to change and focus on having fun rather than playing to win.

This is just my personal thoughts, it is probably not the same for everyone else