Could not disagree more than I do with the idea that this is mediocre/bad football. I love the parity and it is making for great football. I would attribute it to ajustments and preparation made for each week against teams coaches have more film on as the season goes on. Much more entertaining than watching Manning or Brady carve some helpless defense up.
Unlike the NBA where, over the last few seasons, it's been inevitable that the finals will end up being Cavs/Warrios with months of playing for 3rd place until June for all other teams. I will take parity over that any day, and I mean ANY DAY!