Remember, number scoring systems are not absolute, and are still based on opinion.
Giving a game a Perfect 10 opens a review site to ridicule. A perfect 10 means people will point out minor flaws and say "see! It's not perfect! Why'd you give it a 10! BIASED!" It also means some people will blindly buy it even though they don't like the genre/type of game/controls because, hey, it's supposedly perfect!
There is no such thing as a console war. This is the first step to game design.