I'm not a Pixie Duster and go to Universal way more than I do Disney, and I like the Little Mermaid…as does the rest of my family, especially my two youngest kids. So I don't get your point--you're just arguing with opinions, which will get you nowhere.
I've always been more lenient on 3-D than some, but there is such a thing as over saturation. For some experiences, 3-D is the best…things like Transformers, which is non-stop action from start to finish, and T2, which tries to envelope the audience into an experience, are great uses of the technology. That being said, there's something distinguishable about AA's. You can pick your favorite AA in a theme park resort…but you can't pick your favorite 3-D screen. At their core, they're all the same.
The last time I went to Universal I did begin to notice a little screen fatigue. 3-D movies tend to hurt my eyes, and while a ride is incomparable to a full-length movie, having 3-D glasses on through a lot of the day could be kind of annoying. It's nice to sometimes have some rides to slow down on and enjoy something more "real".
I think King Kong could be the perfect type of ride to slow down and take a break from 3-D on. They've done it before, it's obviously possible. While I like the idea of being able to fly through the jungle with dinosaurs and King Kong fighting all around me, I'm already able to do that on Spiderman, Transformers, and presumably Gringott's (don't tell me if I'm wrong though, I'm still trying to avoid spoilers!
). Nobody's denying that 3-D rides aren't cool, but after a while the technology has run its course and can only do so much. I mean, really, how much more can they do with 3-D? Sure, you could say the same thing about Animatronics, but you can make different Animatronics, with different capabilities, motions, etc. in different physical settings. A 3-D screen, no matter what ride it's in, is still a 3-D screen at the end of the day.
TL;DR…3-D is cool and works perfectly for certain types of attractions. But not everything needs to be the type of experience 3-D lends itself well to, and therefore not everything needs to incorporate 3-D. Say what you want about Little Mermaid, but in a park full of big action rides, it would be a nice diversion, and Universal could pull a ride like that off very well (as proven with their old-school rides that are now gone).