I think the Nemo ride is better than the Living Seas ride that was there before. On my last trip I also had a great time at Crush, he was genuinely hilarious.
But it is all akin to me saying that I had an excellent burger, great stuff, much nicer than the local fast food place. Only to then remember that once instead of burgers they offered you haute cuisine.
Nemo makes for an excellent burger, but The Living Seas was more grand, more daring, more mysterious. And worked to enforce EPCOT's overall theme, its sense of place and of purpose.
If Disney at the MK were to replace Pirates with a 'Caribbean Splash and Soak Playground', and the Mansion with a crazy mouse coaster, then a lot of guests, most infact, will enjoy these new attractions. But despite their genuine enjoyment, it will be a step back, a lesser, less ambitious, less captivating park.
Me, I do love Mission Space. Surprisingly, I don't hate the new Imagination either. Like you, I also think the Nemofied Seas is a fun pavilion. It is! But...but when I think of the original EPCOT, I can only weep with regret and a sense of terrible loss.