I understand people being skeptical about NE coaches, but the Flores-headed D in 2018 has been signed better than the Patricia-headed D in 2017 (and earlier) with similar talent. Flores also isn't a slob and seems to have an understanding of accountability, which Patricia lacks altogether. Had the offense been more aggressive in the first three quarters, the game probably ends in regulation with NE winning by more than one score. At one point, NE had more rushing attempts than passing attempts - while averaging less than 4 YPC. They didn't start attacking until they had to, and KC's D is incredibly vulnerable to the style of passing attack that the Patriots prefer. When KC went ahead, it was more about NE blowing it (both players and McDaniels) than KC playing great. When you're a lopsided team with an explosive offense and a poor defense, and you fail to score against a balanced team in the 1st half, you should expect to trail by more than 14 points. If Brady and the offense didn't dominate the KC D so thoroughly in the 4th and OT, I'd more readily by the argument that NE was protecting a declining Brady. He is in decline, but KC's LB's and secondary are too poor for it to matter much, especially when the NE OL is pass blocking at that level.
Relative to their level of talent, the Patriots D has been great all year, and it's the best D they've fielded in years. Maybe that's all BB continuing to evolve and taking another major step forward in 2018, but I tend to think the new DC ("LB coach") played a significant role. The evidence points that way.