Much like players, I guess I look at what they do after they leave Green Bay. The 3 coaches you mentioned, Zook, Menenga, Drayton, are no longer employed in the NFL. That tells me a lot.
I will admit, Bisaccia has a ton of experience as a Special Teams Coordinator, so it's a bit of a head scratcher as to why he's failed in Green Bay. What I do see with his career is a guy that has bounced around to a lot of different teams, but never really advancing. He must have a great football mind, to continually being made an assistant to the HC. However, why hasn't he climbed another rung on the ladder?
Anyway, I don't see him being fired mid season, nobody with a ton of talent is available right now. What I really would like to see is for MLF to say " You know what Rich, I'm good on my duties, you go focus 100% on making our special teams better."