I guess there is a lot to say here, because i'm still one of the guys with the most reviews here and most of them being pretty (what you would call) "harsh", but i don't have too much time right now. So it's a short statement:

I don't like the idea of "professional reviewers" at all. Our basic democratic conception of J2O, as i understand it, in terms of everyone, newbie or not, having the same rights, should not be changed into a system, where some people are "more equal than others". See George Orwell's "Animal Farm" for more info.

The easiest solution for "overrating" is: go ahead and write a more accurate review of the level. If enough other people will do the same, we don't have the problem anymore. That's democracy