I agree with many of the posts in this thread.
However, I really think this emphasis on the schemes being wrong discounts what they have accomplished. This team is hampered in its pass defense by the lack of at least one real animal DE on the pass rush, a LB core that is not particularly adept at coverage and a painfully bad secondary that has to play soft for fear of being beaten deep. BB is making some sacrifices in pass defense particularly to keep from being run on extensively by opponents.
Sure we are producing ugly wins when we win. However, if you really want to see this team struggle, see what happens if BB puts guys on the field that allow teams to run all over them. Instead of talking about 6-3 and ugly wins you will be talking about 4-5 or worse and ugly losses. BB knows that this team is not great against the run but if he keeps his run stoppers out there he can at least control most teams in their running game. His run stoppers are also hard hitters capable of forcing fumbles during either running plays or pass plays. He can force teams to beat them with their QB's. While this is now a pass happy league there are actually very few QB's out there that will not eventually screw up, often without even being pressured to do so. Do most Pats interceptions look like a super athletic play by a DB or does it look more like the QB makes a poor throw with the DB at least close enough to make a play on the ball?
So BB forces turnovers and controls the opponents running game so that his real asset, his offense is not sitting on the sidelines stewing as much as it would be otherwise. Look at how many offensive plays teams are getting on the Pats even with the way BB is playing it, leaving his run stoppers on the field. What the heck do we think would happen if teams were really running wild on the Pats....a very real possibility. Look, it is not like the Pats are top 5 in the league against the run. They are 9th against the run while being 29th against the pass. They are 9th against the run with Vince taking 80% of the snaps on D, Love taking 60% and Spikes and Mayo taking closer to 90% of the snaps on D.
So that is the real genius in what BB is doing with the talent that he has. He realizes that while he can put a combination of players out there that will likely be better in pass coverage, the guys he has for that purpose are truly weak against the run and will end up being run over by even mediocre running games.
What we need especially in the post season where everything including generating turnovers becomes more difficult is more physically athletic, talented players. Schemes rarely win those games anymore. A key play or plays one way or the other, mainly plays that physically talented, athletic players make are the difference.
Do we really think the Giants dialed up a play that called for a receiver to pin a football against his helmut to win that SB? That was a play made by a talented physical, athletic specimen. Coming down the stretch of last year's SB did it look like we were being out-schemed or did it look like the Giants had more physically talented, athletic players making plays for them?
In my view what BB and his coaches are doing with this defense is pretty remarkable. But by the same token BB the GM is making it pretty tough on BB the coach to succeed. He needs more physically athletic players on his defense. He needs one more really hard rushing DE (completely agree with Parcells there). He needs a multifunctional LB to play with Spikes and Mayo, somebody that can actually cover somebody and he REALLY need more physically athletic players in his secondary. The modern NFL with its rules changes will simply not allow much success for the prototypical BB defensive back.
Maybe Talib will be enough. He is big for a CB. He is surely more athletic than the CB's that they have. Maybe he will be enough at least in the secondary. I would bet they will need one more physically athletic player back there plus the guys I talked about for the d-line and LB. That could be enough to get to and win the SB.