You'll be hard pressed to find a coach that doesn't have a blight on his resume. Bottom line is our defense went from a gigantic weakness to a strength. Their ability to turn the ball over literally won games for us, scoring when the offense couldn't. I'm not sure how long you've been around, but pre-Quinn we'd be lucky to get 10 ints in a year, let alone 10 by one player (in two separate years).
The run defense is bad, yes. The reliance on oversized S is bad, yes. But the personnel is also bad. The players we have aren't good enough. With what he's been provided, he's done a fantastic job in Dallas.