Bronco has to be the final sign off on everything, so he can't just pass that off to somebody else.
It seems to me that Bronco wants to be the big picture guy as well as the guy who can mentor players and deal with all their on and off the field issues.
While a lot of people are focusing on Howell as a coach (I think he's a very good Xs and Os guy and those who know football and who are commenting on the defensive problems seem to think so as well), I think he's just not Bronco in terms of leadership and being able to motivate guys.
I don't think Bronco needs to take over as DC again, I just think he needs to spend more time there as a motivator and leader. He has spent most of his time with the offense this season and I think it has hurt the young D guys.