How can Cowboys succeed with Quinn without overhauling bad talent on defense?

The Dallas Cowboys completed one of the worst season in history on the defensive side of the football.

Giving up a franchise record 473 points while also being the second worst run defense in the NFL culminated in Mike Nolan being fired.

Dan Quinn along with Joe Whitt, Jr. take over the defense and regardless of the scheme the Cowboys run, they will need to overhaul the defensive talent that they currently have.