It seems to me that Quinn was traded because having him in the lineup restricted Wade's ability to scheme. Historically Wade's 3-4 defense has been able to disguise who the 4th pass rusher was. With Quinn in the lineup that mystery was gone. Quinn rushed the passer/contained the edge almost every play he was in.
Next season with player 'X' out there the 4th rusher might be him. Or Barron. Or Barwin, or Tree, or Peters, or Joyner. Could be anyone, really. And that's the point. Wade's defense will be better with a player more suited to his 3-4 playing Quinn's spot. (And Quinn could well be better next year playing a traditional end in a 4-3 defense, a defense that aligns better with his skill set.)
AlbaNY_Ram