In those 11 games they scored 29, 20,36, 35, 20,16, 43, 9 (oof), 33, 27, 22, which overall is still very good (I would do the other offenses taking out their divisional games but that would take too long and it still has them at 6 I believe so my point is still sound). I guess you could in theory keep removing teams but at that point you are simply trying to find bad games and saying that defines the offense which you said in your opening sentence does not define an offense.
If it is predictability you have that with other teams as well. You know the Buccs are going to struggle against the Saints. You know the Packers are going to struggle against the NFC West. Going back further you knew Brady's offenses would struggle against any team with a strong front 4 and you knew Peyton Manning offenses would struggle against teams with great corner play (which is why the Patriots always made sure to have great corner play). The Cowboys had a similar weakness to those Patriots teams and you saw it in the playoffs, but having a weakness does not make you bad, because every team has a weakness, the problem is that they could not scheme around it.
Edit: just to point out from a defense perspective I am pretty sure the NFC East was not even the worst of the divisions. For sure the NFC North and AFC South were worse and while Denver was a solid defense KC got to beat up on Chargers and Raiders awful defenses.