I see what you are saying. Let me throw something out there...
The defense scores 2 TDs, causes fumbles, sacks, interceptions, great field position, etc, and carries the team to a 31-7 victory. Still thinking keep Cally and get a new DCoordinator? In this scenario, a punt return also goes to the house for a 50 yd score, while the offense puts up one touchdown and a field goal. The game is won convincingly. In a different scenario, the offense scores four TDs, a FG, and win 31-7.
I personally would be happy with either scenario, however it would not fuzzy up my thinking. When the season is over, it's over and done. Either 6-6 or 5-7, bring in a new coaching staff and let's move on.