Why don't we just support a rule that only allows games to be rated between 90-100. That way, no one can complain about a game getting a low score. Actually, we would probably have people getting angry when a game gets a 90 or 92 ... maybe we should just get rid of scoring entirely since scores are already so messed up with a 7-8 being bad or below average.
I don't really see the purpose of reviews in their current format. Every game gets at least a 7-10 score so everything is, apparently, good/great. If every game made is worthy of such a high score (only exceptions being low budget games which don't have enough money to put ads up on review sites) then I don't need to read a review to tell me this is the case.
Even abominations like Homefront and Brink ended up with a metacritic score of 70 ... put enough money behind a game and you will get a 7-10 score it is just a fact of life now.
As far as Uncharted 3 goes, 8 out of 10 sounds about right for the second sequel to a popular franchise. In a perfect world, sequels would get progressively lower review scores on the basis of their lack of originality. The only exceptions would be games that completely change the formula from the original, or ones that have major innovations that mix up the experience and make it something completely different.
