In all honesty, I never found 20,000 Leagues to be much of a ride to begin with and really wasn't all that affected when it left. The same can't be said for Horizons, I miss it dearly.
I was most affected by the loss of a big, beautiful water element.
-Pirates of the Caribbean (prior to Jack Sparrow) -- Rose-Colored
I don't think that's necessarily Rose-colored. The Davey Jones thing is kind of forced, plus his movies weren't good. As are the Sparrow moments, which require an understanding of material outside of the ride. I think the best rides stand on their own, and prior to Jack Sparrow those scenes were just fine.
Now, I also don't think it's ruined PotC. It's a small downgrade, but nothing big. Anyone who thinks it's a dramatically worse ride now is either completely absorbed in nostalgia or just really liked the old upper grotto.
-Mickey Mouse Revue -- Rose-Colored
There are people who liked that more than Philhar?
-If You Had Wings/Dreamflight -- Rose-colored
-Space Mountain (prior to audio) -- Rose-colored
No, it's not rose colored. It's preference. It doesn't stop Space from being one of my favorite attractions, and I get that I'm in a minority and that's fine. But I don't prefer silent SM because of nostalgia. I prefer it because I prefer the eerie lack of a soundtrack on SM.
-Body Wars -- Rose-colored
-Cranium Command -- Borderline
Disagree with both of these, because Body Wars has been replaced by nothing. Unless something is an intrusion on theme, which BW was not, getting rid of it for nothing is a negative. I don't terribly miss Body Wars, but having another attraction to do in Epcot would be a good thing, even if it's a dated ride. Body Wars certainly could have used an update or a complete replacement, but it didn't, it just got closed.
Cranium Command, though, was awesome. So that's even worse.
Though I'd rather have Horizons, I think this shouldn't be on the list, as it's entirely a matter of preference. Some people are going to prefer a space simulator that frequently falls in to disrepair over an audio-animatronic extravaganza. While I disagree with them, I also think that's not objectively weird.
-The Living Seas (prior to Nemo) -- Rose-colored
No way. Epcot is much better without single-property characters being shoved in to the concept for an entire pavilion. Nevermind the ride is pretty awful.
-Superstar Television -- Rose-colored
-Monster Sound Show -- Rose-colored
No. You cannot convince me it makes sense to like Sounds Dangerous more than Monster Sound, and there's no way you can convince me Sounds Dangerous is a worthwhile attraction. Monster Sound was kind of interesting. Definitely not an attraction I miss, but it's also definitely be downgraded.
Now, I actually think Idol is a nice concept, and while I don't like the TV show, I have liked the theme park show the couple times I've done it. I think that one is a preference thing. I'd call it a push, but I certainly wouldn't call it rose-colored (or justified).