Yeah, it's a near impossible task. Baseball has batting averages and ERA's that makes it pretty easy to quantify player performance, at least relative to other sports. But it's not as irrelevant as you paint it as at least in some limited examples, teams, player scouts, etc, will at times and in certain situations use the information collected and analyzed by PFF in their own player appraisals. It's still pertinent information.
It's like any other data. It needs to be put in perspective in order for it to mean anything. Seldom do we find a definitive stat, appraisal, or ranking, but they can be used to help paint a picture. As we discussed earlier in the thread, our weakness on offense is with the interior OL, and the information contained in PFF's player grades supports that observation.