The New England coaching staff is returning almost the entire roster from the previous system. Like with players, coaching consistency wins.
It's not a surprise that New England Patriots head coach Bill Belichick is the longest tenured head coach in the league as he enters his 16th year with the team. Consistency in the coaching ranks is just as important as consistency with the depth chart, and Belichick has done a good job of creating a fantastic coaching roster.
This off-season, special teams coach Scott O'Brien retired from coaching to assume a consulting role in the front office.