Well that's my point. I'm not faulting MW2 for charging 60$ because that's the common accepted value for console games in this market. I'm faulting MW2 for giving me a $40 value at a $60 price. In otherwords, I'm rating the relative value of the product and enjoyment I get out of said product, at a ratio the money I spent on the product. You're right, value is strictly an opinion, and always will be. Its part of the definition of the word 'value', and my opinion is the game isn't worth a retail price. Therefore I fault the game not delivering an enjoyable enough experience for the price tag it holds.
Just to give an example to what I'm saying here is... a game like Peggle gets a 8/10 when it costs $1-$5, but a game like Assassin's Creed 2 can get a 7 or 8/10 because it costs $60. Is Assassin's Creed a better game than Peggle? Absolutely, but you can't justify the production values of a game that costs 12 times as much as another, let alone in a completely different genre. The idea of value lets us gauge how good a game is based upon its overall worth... ie. money vs. enjoyment.
I mean think about it from a car standpoint. Would you fault Toyota if they charged $15,000 for a corolla and the trunk was missing? Sure would, its because you're paying full price and you're not getting the full benefits of owning said car. Or a little less extreme, if you compared two cars of the same price and one had more trunk space, got better gas mileage, and handled snow better... wouldn't you only purchase the other car if it was cheaper? I know I would. Only way I'd buy an inferior product would be at a cheaper price, thus making its overall value for use ratio higher. Economics is what makes the world go round