I don't think most people are complaining specifically about the actual scores, but with regard to consistency. (Comparing scores)
I would love to see reviewers resorting to harsher scoring, but it has to be consistent. Halo 3 and GTA IV are far from perfect for example, they can be easily topped in so many ways (both technically and from a game design perspective, you can pick out the shortcomings easily which could have been improved on significantly), so providing a score less than perfect leaves room for other games to top them and push the devs to do better next time.