The problem I'm seeing with all of this is that not only reviews are based on opinions. There's also opinions towards the review and the reviewee. And honestly I could see someone thinking "oh, HE wrote a review. HE's an idiot, I'm going to weight my opinions fully against his review and downvote him."

Even if that person made a decent review, their opinion becomes worthless. Many people could have different opinions towards a review, but I've observed that people within this community would have a tendency to more quickly mark down a review than to mark it up.

Also when you have a rating system based on a person's input, it puts pressure on that person which could cause them to withhold their opinions in fear of being harshly judged negatively. It's already bad enough to be posting your opinions on the internet, accessible to the world, but by having people rate them, it causes further hesitation. And honestly I'd rather read somebody's non-judged opinions; whether it differs or not from my own makes no difference but having vast inputs would make for the best final rating. We don't want other people's valid inputs withheld and we certainly don't want to keep people from conducting a review simply because they disagree with the majority. That would be counterproductive to the whole idea of "fixing" the review system. The review system already isn't used as heavily as it should be. Why deter people further?

As an alternative to a user-based rating system, why not a review-based rating system? If a review is, in your opinion, invalid, click the thumbs down button. If it is, click the thumbs up button. But don't, of course, keep a count on the user's profile of how many thumbs down or thumbs up they've received because that just deters people to follow a higher-rated person's opinions so they get higher ratings while a person on the lower end continues to drop. Also keep in mind that there are juvenile reviews from the past. People grow up, learn more, and change. Those reviews may not mean anything to the reviewer's overall present-day review quality, so would it be fair to use that against them? (I have no opinion on that matter, you decide)

I also second Unknown Rabbit's response. That would create a mess... And initially, ratings will definitely be bouncing all over this place if this system were to be enacted. Its just an overall bad idea. A review should be based on the material included in the review, there are already filters enacted and used and I'm sure they would continue to be used; user-based rating systems just aren't a good form of quality control.