I agree it probably wont happen and it probably wont happen for the wrong reason: pride. Like you said, its not a good look for the HC and the GM. Firing Dennison is an admission that a mistake was made; a big mistake.
McD has enough on his hands with this defense. He needs to have someone who is 100% competent at OC bc McD is a defensive guy. And who are the main minds on offense? Dennison and Castillo: 2 guys that have combined to do absolutely nothing in the NFL (on their own, as the head guys).
Keeping Dennison for the sake of saving face is no different than cutting off your nose to spite your face.
And like i said 2mo ago, forget about Tyrod. Is Dennison the guy you want nurturing a 1st rd QB for the next 3-5yrs? No way.
So rip off the bandaid. Just do it.