BO'B's situation is somewhat similar to Macs: Neither has been given what is required to do their jobs well. There may be something like enough evidence that Mac's upside is simply not adequate for the team to anoint him the "franchise" QB. I don't think there is enough such evidence re BO'B. He is trying to do two things which are somewhat in tension with one another. When Josh was Mac's coach/mentor, his attention was steadily on so curtailing Mac's responsibilities that he could achieve success. Bill is trying to support Mac;s devlopment while at the same time establishing a more complete version of the offense, even as he is somewhat held back by Mac's limitations and nearly prevented from succeeding by the poor roster building under GM Belichick. It seems to me that this year's roster is actually worse than the roster Mac had to work with in his rookie year. Between serving two masters - building a new offense and tailoring that offense to Mac's limitations - BO'B has not had a chance to make it all work.
I'l confess I find many of BO'b's playcalls baffling, but I suspect he is working around far more problems than are apparent on first glance.
I would not object to BO'b's sticking around as OC, but given he is quite likely to move on at some point anyway, perhaps in pursuit of an HC job in the NFL or in college, and given there is a case to be made for a younger guy with a fresh approach, neither would I sqwawk much if he were to be shown the door. He hasnt done his job badly enough to lose it, but neither has he done it well enough that moving on is unthinkable.