The preshow is an amazingly lackluster collection of movie screens confining the stars of the attraction to television monitors and the story is hopelessly convoluted, contorted into a pretzel in large part to justify the GotG (again, stars of the attraction) being "somewhere else" so they could cut the scene in the concept art they have been showing off for several years.
And you're correct - during the actual roller coaster portion, the visuals aren't particularly important. The ride succeeds on physical sensation and the auditory pleasure of four decade old pop songs. That's a good argument not to build the same coaster-in-the-dark over... and over... and over, since WDW built its reputation on elaborate visuals, NOT physical thrills.
And what, here, is "new technology"? The projection effects are actually fairly basic. I'm genuinely surprised there aren't any really interesting visual effects, projection or otherwise. I mean... we all expected SOMETHING to happen with the giant ball, right? Instead, its just... a moon.
Let me ask the experts - what's innovative here? I mean, the one "Wow Moment" people keep pointing to was done much better at a Hilton hotel 25 years ago.