Belichick to his credit listens to the input of his coaches in personnel decisions from draft, to FA, to trades.
Unfortunately, the offensive coordinator isn't that good at personnel. He's horrible at it. Michael Holley in his book specifically says they drafted the bust RB Laurence Maroney because the coordinator's kid brother coached Maroney in Minnesota. The Broncos then wasted a 4th rounder trading for Maroney, who quickly flamed out over there.
Look at offensive acquisitions the past two seasons, a bunch of ex-Bronco and ex-Ram players, or rookies worked out by the coordinator:
Danny Amendola
Greg Salas
Tim Tebow
Brandon Lloyd
Michael Hoomanawanui
Kenbrell Thompson
Aaron Dobson
Josh Boyce
Zach Sudfeld
One more year of bad offensive acquisitions and this offense will go downhill. Too many misses. Amendola is going to HURT the team for years to come, $29M over 5 years down the drain which is also going to make it hard to keep Edelman.