I think Bill's fundamental flaw is that he's too willing to listen to and/or hire his buddies. That's the root of a bunch of the bad draft picks and the questionable coaching picks.
I still think it's way premature to say Bill can't coach anymore or that his offensive or defensive systems can't work. The defense looked decent enough before everyone got injured (and the bad offensive play makes the defense look worse than it is) and the skill level of the offensive players is too low to tell if Bill's desired offensive system would work or not. To be clear, the fact that the skill level is so low is on Bill!
So I'd like to see a major rein-in of Bill's GM powers.
As for what's left of this season, Bill's on the horns of a dilemma. If he tries and manages to right the ship somewhat that means a mediocre record and the pain continues because they won't be drafting high enough. On the other hand, a crappy record is personally and professionally painful, as it should be, and I'm sure tanking is offensive to him, as it also should be.