Judging the performance of a position coach by how a defensive unit as a whole performs is dubious. You can't make the inference you're trying to make.
In any case, even if he was a stellar position coach, it wouldn't mean he would be a stellar coordinator. Look no further than Kevin Coyle. And even if you're a stellar coordinator it doesn't mean you're going to be a great head coach. It's too hard to project.
I just don't think you help yourself by targeting the coordinator of the offense or defense du jour. It makes it too easy to blind yourself to the true abilities of the person you're dealing with. We've made that error already a few times now and should be learning from it. Both Cameron and Philbin seemed stiff and bland from day one, yet we (and Huizenga and Ross) allowed their recent successes to overwhelm what in retrospect seems obvious.
I don't see how Malzahn is a better option. He is a great college coach. I just don't see him being a guy that #1 would even want to leave for the NFL, and #2 have success in it. Chip Kelly may be able to beat up on the NFC East, but because the offense he runs, he'll never have the defense necessary to make a Super Bowl. He's beaten up on the NFC East, but his team is flat out too soft to ever get through Seattle, and San Fran.
Dan Quinn is a phenomenal football coach. Jason Taylor has called him the "best defensive line coach I've ever seen" he's been an assistant head coach, he's been a successful position coach, a successful defensive coordinator. He's coached under Nick Saban and Pete Carroll. You are really overlooking the fact that the defense was that good in his first season as an NFL Defensive Coordinator. You don't realize that that defense could not be any better. They are maxed out. He maximizes every single player on that defense.
He's enthusiastic, and his players love him.
He also convinced Michael Bennett to sign with Seattle the day after they signed Cliff Avril, and had Chris Clemons, and Bruce Irvin on the roster.
“He’s not married to a scheme; he wants you to grow, He changes with the players.” “He’s a master in the film room.”- Michael Bennett
For Dan Quinn to become the Next Big Thing in coaching, his defense had to leave no doubt in Super Bowl XLVIII against Peyton Manning. In Quinn’s mind, that meant watching two years’ worth of Manning snaps in the week after the NFC Championship Game.
That’s every snap Manning had yet taken for the Denver Broncos, watched, re-watched and mentally catalogued; 1,479 throws, 967 handoffs, 131 touchdowns, 24 interceptions and more audibles than there are minutes in a day.
Says a close friend of Quinn’s, “He’s definitely an obsessive.”
“It’s about being developmental,” Quinn says. “How much can you find out about this player? And what can you draw out of him? It takes a lot of time and effort. Those relationships are really important.”
http://mmqb.si.com/2014/08/06/dan-quinn-seattle-seahawks/