I don't think you can use an objective scoring system that's purpose is not comparison. You compare the value of one game over another using numbers. The context provided is a cop-out because the only reason the score is there is because their readership likes to get angry and fight over scores. The scores are unimportant if they are not there to be compared. Why give them prominent status on the review page other than to generate page views and get on Metacritic?
I prefer the 'Buy - Rent - Avoid' scale more, honestly. It's direct and has no foundation for comparison whatsoever.