I don't think that the Pats' D is bad against the run. I just worry that we can be gashed, as we were in the Buffalo game. The reason why I think it is pretty simple: because we've played one good rushing team so far, and they ran all over us.
The Falcons were running for 3.4 YPC coming into this game, against Miami and Carolina. The Jets ran for 2.7 YPC against Tennessee today, and did well against a Houston run defense that got absolutely annihilated by JAX today (184 yards, 5.9 YPC, 4TD). So the Jets' running game got shut down in 1 non-Pats game, and did pretty well against a terrible run defense in the other.
To reiterate: I'm not saying that the Pats are bad against the run. And as bad as tehy were in week 1, I fully expect them to improve as the year goes on. But I'm definitely not ready to write off the Buffalo game on account of the fact that two decent-at-best rushing teams haven't done much against us since. Not saying we're bad- just that I haven't seen much since week 1 to swing me either way. If we can do well against the run next week, I'll be convinced.