Review scores are pretty useless to give you a quick idea of a game.
I like Gamespot's pros and cons list (unfortunately the rest is mostly bad) and on Eurogamer I read the last paragraph first, since that usually also sums up the pros and cons. The score is meaningless without context.
Rating games is giving a personal opinion. The only way it would be meaningful for someone else if it uses a correlation engine. A system that tries to predict what score you would give a game based on what you and other people rated other games. Basically a better version then finding a reviewer with the same taste as you.
I don't know if 30ish professional reviews is a large enough base for something like that but it would be an interesting extension of Metacritic. By providing your own honest review scores to what you have played, Metacritic should be able to predict what you would think of a new game after the professional reviews have come in. Of course that still would not work if all the professional reviews hand in 10's to get hits :/







