The Patriots' problems start at QB. Brady had a huge negative impact on this game, and with his legacy, the team just can't do a thing about it. He used to win by out-thinking opponents, and delivering great throws (albeit not cannon-velocity).
Noticeably, he's slowed in his decision making, and the whole 'blame his receiving corps' is overblown. Today's pick-6 is on no one but him - he was absolutely awful. You go back to his sulking when the receivers weren't playing well, and frankly I won't be sad to see him leave in the off-season. Not only is he not that good any more, but he's a huge part of a problem.
And then the Pats force 4th down with 1:40 to go in the first half, tied 10-10, Dolphins in their own end. They had 3 timeouts. Belichick let them run down the clock, then ran the ball to run out the half. WTF are you doing, Bill?
On the Dolphins' final drive, the defense looked mentally beaten (hands on hips, heads hanging when they gave up a play ....).
I'm happy to have Sundays freed up in January - lot of snow fell this week, skiing should be epic.