Brady opened the season with this group and led 2 failed drives because his WR's and blockers were not executing consistently. People here forget that Brady was not undefeated in the last 7 seasons. When they struggled so did he, and while he was sometimes able to overcome them or will them to elevate their performance in game, that's what makes him a HOF'er. You can't reasonably expect that effect from ANY other QB brought in to that kind of situation. And for those concerned about Cassel's ability to motivate his teamates to perform for him, remember they are paid professionals and Bill expects them to be self motivated or it's on them...
Beyond 2003 and 2004 this defense has not performed consistently at an elite level, sometimes due to injuries, though Bill generally gets them going at a higher level more consistently as the season progresses. I think he can bandage this D fairly effectively over time, it's one of his and his systems strengths to mask weakness via scheme. It will be tougher to do that on offense since Brady was his main masking agent on that side of the ball. His most logical course remains to let the system and the players in it do the masking, as they did in 2001 through 2006, but that will equire 11 guys executing at a high level within the system to accomplish that.
It's too late now to make substantive changes in personnel because they won't be capable of executing within the system, and that will make it impossible for many others who can to continue to. Most HC's in that predicament will over react to pressure to just win now and screw the long term impilications of abandoning a course or system because their jobs hang in the balance. Bill knows his does not. And he's one of those rare birds who truly has the courage of his convictions. They got him this far in a 30 year NFL career and resulted in 5 rings in the last 2 decades for teams he coached according to his convictions. And while his convictions do not always carry the day, they have more often than not over the last decade in particular.
And don't forget when opening these threads that the OP's biggest fear is really his secret hope. Because it would validate what he's been saying here for a couple of seasons now. He seldom posts here when things are clicking...