4 games of over 200 yards rushing allowed. Supposedly no other team has allowed more than 2.

You can get away with letting the other team run the ball if you're up 14 with 8 minutes left in the game, but you can't get away with that if you are playing at SF or Philly in January. They will stomp you into the turf.

Barry does not have a track record of being an above average DC. Never has. Even a 'good' season for him is middle of pack.
There are times when he's had a good gameplan and players executed poorly, sure. From what I've heard he's regarded as a nice guy without an ego, not some kind of defensive genius. You can find better, but MLF won't.