I liked your graphical representation but, bottomline, all is reduced into: people don't want to read a lot of text to see wheter its a good game or not. Any sort of numeric or graphical representation of the "quality" of the game is there to help people make fast decisions.
I am not saying numeric rating are perfect or even desirable (the best would be you to browse sites and read the reviews), but any summary of the reviews can be overused until it has the same problems ("why MW2 has less substance than SF4?", "The reviewer said "Seth is so damn cheap", ergo, he is dumb and unable to have an opinion"). I do preffer, however, when the numeric rating is an average of several numeric values... at least then it doesn't look like they pulled the number out of thin air.
I am not saying numeric rating are perfect or even desirable (the best would be you to browse sites and read the reviews), but any summary of the reviews can be overused until it has the same problems ("why MW2 has less substance than SF4?", "The reviewer said "Seth is so damn cheap", ergo, he is dumb and unable to have an opinion"). I do preffer, however, when the numeric rating is an average of several numeric values... at least then it doesn't look like they pulled the number out of thin air.