It's depressing there are people here who have never heard Yub Nub - not because that song is any good (it isn't) but because it means there are people here who've never seen the originals. George really buried them deep

I was on the cusp fortunately - my dad had the original VHS versions and those are the ones I watched growing up. Had he not shown us those, the first time I would have seen SW would have almost definitely been the Special Editions in '97. I shudder to think how many people haven't seen Sebastian Shaw as a ghost.
Yub Nub is
such a lame track. Yes, Return of the Jedi isn't the strongest (or most serious) film but the saga deserves an emotional, cathartic close. Hell - the Luke climax is enough to warrant something more powerful than Yub Nub. As has been said, sure, we get the Pyre scene, but it needs that final jolt of energy to get the spine tingling and the tears rolling. These characters have been through a lot and seen a lot of shit at this point.
Victory Celebration is such a beautiful track. I don't even mind the celebration montage around the galaxy (sans shitty, out of place CG). It drives home the idea that their actions had significant effects on the galaxy. I can't really wrap my head around it now, but I imagine that with only the three films in their original state, the audience really wouldn't feel the significance of the destruction of the Death Star and the death of the Emperor when the movie only ever focuses on the small group of rebels celebrating. The montage solidifies the greater, significant good they've achieved.
Oh and to "I can't imagine the characters dancing to Victory Celebration like I can with Yub Nub" - Victory Celebration is non-diagetic music. It captures that tribal, raw sound of the Ewoks, but I don't think they're actually meant to be dancing to it. They're dancing to their own tune (probably something lame like Yub Nub).
Besides this, effectively all the other changes are pretty rubbish. Some I really don't mind - they're not super intrusive but are generally unwarranted. I could actually put up with all of them. HaydenGhost is a really daft moment that comes close to being a dealbreaker. The "No. Nooo" is an actual dealbreaker and is the sole reason I don't own the Blu-Rays. Arguably the single most powerful moment in the entire series - the culmination of both Skywalker characters (regardless of the PT), the climax of the trilogy and brilliantly effective in its raw emotion and simplicity - crisp, character-defining single action, and George takes a big, hammy, soppy, raggedy shit all over it.