I respectfully suggest that the only thing suspect about the defense is that the offense is not carrying their load. A few more offensive PPG (to allow the defense to play with a lead) and a few longer offensive drives (to give the defense more of a blow) seems to me to be the best remedy.
What QB now won't be "feeling" Brooks on the pass rush, after how he bloodied Brees? Brooks is having an All Pro season. Aldon is clearly regaining his stamina and returning to form on the other side. Lemonier is the best back-up pass rusher that the team has had in years, to spell Brooks or Aldon, as necessary. Justin Smith is still Justin Smith. Tomsula is getting excellent performance from Dorsey, Jerod-Eddie and Dobbs, while McDonald heals for the playoff push. Do you doubt that Tomsula will get production from Tank and Dial, as the season rolls on? In Tomsula, I trust.
What TE or slot receivers look forward to have their sacroiliac crushed by Bowman or Willis for a lousy 3-yard catch?
Reid and Whitner coordinate like they have been playing together for years. Yes, Reid has to be smart and stay healthy.
I agree that the CB's are only as good as the pass rush. There are no shutdown corners on this roster. Brown's loss to injury, if it extends into the last few games, will definitely hurt the depth situation, at a minimum. The defense had to adjust to his loss, on-the-fly, in the 4th quarter vs NO, and that wasn't as smooth an adjustment as was needed. Hopefully, a week's practice with Brock and Wright, etc in their new positions will remedy that situation. Can Rogers hold up? Yes, with a pass rush. No, without one. Can Morris contribute, if there is another injury at this position? That would seem to be a big gamble. Will Cox be re-signed, if Brown is going be out for the year? Who knows? I do know that Drew Brees is one of the league's best at running a 2-minute offense and Sean Payton can certainly scheme to get Brees open targets, even if it is Brees 3rd or 4th option on a play. If the Niner offense had moved the ball for only 1 or 2 first downs, late in that 4th quarter in NO, would anyone really be questioning the patchwork defense that was needed to finish that game?
Just for kicks and giggles, let's see how NO plays tonight vs troubled Atlanta, after getting beat-up by the Niner D only 5 days ago.