I think that's the problem, your use of the word mostly.
Tyrod is part of the reason the Bills were around .500. And those reasons don't always show up on the stat sheets. Missed throws and missed reads. Bailing on clean pockets. Slow pass release. No two-minute offense.
It's not a crusade to question Tyrods effectiveness. I'm still 50/50 on him. I was unbelievably frustrated with him at times and he feels a lot like Fitz. Exciting at times, can do some things but will never carry a team.
And McDermott, having talked to Tyrod and being a reported film junkie, should have answers to the why and what happened in those plays. Hopefully this decision to either extend Tyrod or not, is an educated one.