facemaker329:
Except, you run into problems with those people who weren't 'burned'...the GM had legitimate reasons for doing what was done, but the player cannot/will not acknowledge that side of the matter.
I've seen that come up far too often to think that it wouldn't wind up becoming problematic with such a feature.
Ultimately, the one review/rating system that I can trust to not be influenced by someone else being petulant, petty, or just having a bad day somewhere along the line is my own opinion...and even that can't entirely be trusted, because I've initially thought stuff was better than it turned out to be after consideration, or something I didn't like ended up being something I really enjoy (like Depeche Mode...not a fan in high school and college, recently rediscovered them and have a totally different appreciation for them now.)
Word.
I had a situation like that, where I player I ended up removing couldn't see why I had to do so, and if we had reviews, he would likely have many unflattering things to say, based on the last comments he graced me with before leaving.
As a GM, it would be disheartening to see someone's bad attitude possibly turn people away from my games due to one person's pettiness.
I don't see a way that a public review system wouldn't be abused and cause a lot of bad feelings. It would be rather stressful for something I come here to do for fun. You could solicit opinions from other players, but a public system I believe would cause more harm than good.