You're entitled to your opinion, but I think that three things are evident.
1. What made BB great was his willingness to listen to others (especially Ernie) even though he didn't show his cards to anyone. Towards the end of his regime, though, it seems to have been a reign of terror and those who questioned his decisions (particularly his mad, post-McDaniels offensive coaching structure) like Damien Harris, Meyers and, apparently, Hoyer, were shipped out.
2. None of BB's former coaches have had great success as Head Coaches elsewhere, not because they weren't very knowledgeable about football and excellent position coaches, but because of their failures in relating to their players.
3. The players last season loved Mayo and really bought in to his leadership (a Gatorade shower after his first game!)
They were let down by terrible GM-ing (14 different players on the O-Line, only one survivor from the draft) and appalling coaching by AVP and Covington.
I don't see Mayo as having been "self-important" but inexperienced and unsure of himself. What he needed was a consigliere to ease him into the role. What he got was Eliot Wolf.
Anyway, Vrabel is here now -- but Wolf remains.
The Patriots have $32 million in dead money (people who are being paid not to be here!) of which over 20 million comes from Godchaux, Peppers, David Andrews, Strange, Bentley, and Bourne. Were none of them good enough even to be backups? Or is this more player selection on the basis of whose guy you are, not how you can play?