While many say the redskins D was at a minimum respectable and went to pot with the switch to the 3-4, I think this arguement assumes a D's ranking should be in yards allowed or the only slightly better stat, points allowed. For years, we had good or even top 3 defenses by those metrics. However, they never got off the field! For years when it came to the 4th quarter, you knew our D would tire and eventually let in a score on a short field.
Yes, our O wasn't moving the ball, and the field position sucked. That said, when we were down 2 with 4 minutes left in the game, how many skins fans knew if we punted on 4th down, we won't see the ball again? When you look back at how many close losses we had, how many possessions did our O have?...and in the 4th quarter?
So it doesn't seem crazy to me for a coach to come in and say "making them punt from the 50 yard line is all well and good, but we don't have an offense to drive 80 to 90 yards for a score. How can we force more negative plays from the opponents offense? Hmm league wide the teams who seem to do this best seem to be running 3-4. Ok, we will give up more big plays, and our ranking might suffer, but we didn't have a winning way if we stayed pat. Make the switch."