The Pats defense is also 7th in FootballOutsider's "Drive Success Rate," something they ended up at 30th in the league last year. I'm guessing this is a similar formula to the DPS that you cite.
We can talk about bend don't break, but the Patriots are yielding way less yards per drive than last year, and they are still causing turnovers at the similarly high rate. The result is a defense that, so far, is good in its own right. Certainly good enough to win a Super Bowl with this offense.
I agree the corners are playing well. But the safety play hasn't been great. I rewatched the Buffalo game, and neither Gregory or Chung played particularly well. Wilson struggled a little bit, and one of the few plays Ebner was in on, either he or Wilson blew for that Smith TD.
The Patriots seem to be experimenting at that position, too with rotating personnel. We saw a Gregory-Wilson combination on one drive. I think we also saw Chung-Wilson; though the most common unit remained Chung-Gregory. Wilson would come in and play a cover-3 where he'd be in at that box as the play setup and then sprint back to the deep middle when the ball was snapped. That's what they were in when Smith caught the TD, and I don't know if Wilson didn't get back fast enough (what Bedard says) or if Ebner is to blame for letting Smith go right by him.
Either way, safety play is probably the weakest link on an otherwise strong defense at the moment.