I'm with
@LittleBuford on GMR in that I don't think the whole was equal to the sum of its parts. It was an impressive attraction taking into account the elaborate sets and number of AAs and the concept sounds good on paper. I always felt it just fell a bit flat, though, and wonder whether any amount of sprucing up the existing attraction with new technology could have fundamentally changed that. I suspect part of the issue was that it was such a slow-moving ride on such massive vehicles that it never really conveyed the charm or dynamism of any of the movies portrayed nor felt truely immersive. I don't think a slow crawl through a new Avengers scene, for example, would have changed that.
So, I get why people enjoy and appreciate the attraction as a work of theme park design, but as an actual attraction I think it was just ok.
Splash, of course, is a different beast where the ride mechanics will remain the same and its popularity is such that it probably couldn't handle many more people than it already does most days. They really just have to make sure they don't screw it up and somehow end up spending a lot of money to make a less popular attraction.