I have a few things to say about this.
In terms of our QB play, 2017 = 2008 without Dwyer. I gave up counting the number of times Nesbitt missed reads and threw bad passes that year. Having Dwyer around made everybody look good. I was confirmed in this by the Birddog, the chief Navy blogger of those days. He broke down several of our games and said more then once. "If this was Kaipo, it's a touchdown." TM showed the same traits as Nesbitt did his first year: a reluctance to make the pitch in time, loads of missed reads, and poor passing mechanics. Did this matter, you ask? Not much. Dwyer was there and ran us to victory more then once. If Mills was still on the team, I'm betting he would have done the same. Benson has performed better then anyone had a right to expect this year, but Mills was what we needed in the second half against Miami and UVA. I do think that TM will have competition at QB next spring and, while he has the inside track, he should remember what happened to Jordan and be on his toes.
I might add that the AB blocking in '08 wasn't all that hot either, except when Lucas Cox led the play. Perhaps Pnchez-Mason can provide that next year. Cottrell is pretty good out there, but we need a Cox or Allen to make it work at top level.
For the D: I read this thread and my first reaction was, "Make up your mind!" When we ran more complex schemes, everybody here complained about it because it "… makes it hard for the players to react and play football!" Now, Roof has simplified everything and we complain about how "pure vanilla" the D schemes are. As I said in another thread, I think our main problem is in our DL. This goes back to losing four DLs to transfer before 2014. We were ok that year, but those guys would be redshirt seniors this year. (True, we are better off without at least one, but I digress.) When we had Gotsis things were better; we have to hope that another player of that caliber is in the works. As his example shows, a lot of DL recruiting is sheer bum luck.
On coaching in general: I agree that the team got disheartened this year, probably by our two early one-point losses. That was ok for awhile, but you could tell that if things went badly in a game we thought we should win (Duke, iow) or we looked overmatched (Ugag) we stopped playing with the necessary level of intensity. Some here have blamed the coaches for this and think they should have been able to counteract the feeling. I've played on a team like that and I can tell you that my coaches knew what was going on, tried to stop it, and it didn't do one lick of good.
Finally, I don't think the talent gap is as great as people make out. The rankings for recruiting classes are mostly bushwah beyond the top 10 - 15, imho. We have the athletes to make the system work, but, remember, this was a very young team, especially on offense, and we lost several prime athletes to injury or dismissal before the season started. That didn't help.