I don’t see why people are so disappointed that the prequels didn’t include some mind-blowing revelations that would change the way we looked at the OT. Adding needless complications to a prequel of an already existing franchise tends to feel contrived (case in point: Star Trek Discovery). Even then, they already introduced some ideas people weren’t expecting, most importantly the clones being the good guys and the Republic falling from within.
I don’t think anyone’s disappointed by it. At least to my knowledge. Personally, if there really was some trick about Palpatine not actually being the Emperor or not actually being the big evil guy in control, I think it would’ve been really awful.