I agree with your premise that no one thought we were going to have an undefeated season. There are a ton of fans and media that looked at this year as rebuilding given the players we lost.
The Defense can improve with better play, scheming, rotating in other players possibly, but the one area of concern that is valid is McDermott’s coaching decisions. It is absolutely irrefutable that he has consistently made some head scratching calls - especially in critical moments. The troubling part is that he seems to not learn from his previous mistakes.
The real hope is that we go on a heater come play off time and McD is not put in a position where one of his calls is critical to the outcome of the game. It can happen.