Well to address all of you at once.
Punchy, after complaining that reviewing a kid's book on a different set of criteria is bullshit, it is eyebrow raising that you would performance score things because you think the group is pissy, that is neither fair to yourself or the book.
Zero (and to a certain extant Eli) - Average will change with the quality of the books being published. Is Incognito Bad Influences an Average book compared to the majority of the books being published? No, it is more than average. Is it average compared to the output we have seen from Brubaker (and by extension Phillips)? I argue it is less than average, being an inferior product from the team. If I am reviewing a Vertigo book, I will have higher expectations than if I am reading a Marvel or DC superhero book. It's just the nature of the beast, whether that is fortunate or not is a matter of opinion.
Eli, it's a philosophical debate and thus will never have an appropriately satisfactory answer. Pirsig went on a journey to discover the nature of Quality and found out more about himself and his relationship to his son. To a certain extant, all critics use different values for every item they discuss. The review you posted of Superman by Ebert reads differently than the review he wrote in Decemeber of 1978. There are many reasons for that, Motion Pictures are different now than they were then, so looking at the movie now requires that information. He may have different views on Donner or Reeve or may be informed by the less than capable sequels in the franchise.
Brubaker and Phillips do create create work that is better than the majority of the rest of the comics on the shelf. However, that puts their work in a different place. I scored the first book an 8, I think I would stand by that today, even though I might be more willing to give the entire mini a 9 or a ten, that issue doesn't work as well as the whole series does together. Punchy even qualified his score saying it was a 9 cause Sleeper and Criminal are 10s. Bru and Phillips have given us more, thus a ten from them is not the same as a ten from anyone else. It is more like a 12 or a 13. It would be disingenuous for me to score this book the same as I scored the first one, it is not as good of a book. (And I made my score with out looking at my previous score and the group as a whole scored the book lower than the first book, as it should be, to the degree you felt will be largely individual)
We talk about ymmv and stuff, because as much as objectivism is a goal of critical thinking, it is always merely a goal because the pursuit in and of itself is subjective.