This particular trend goes back long before Rob Ryan, you're right. But this isn't Dennis Allen's defense. Rob Ryan doesn't have a set defense. That's why the knock has always been on him that his defenses are too confusing for his own team and do the opposite for the opponent as a result. He's been in a lot of places and been fired every time.

Why do you suppose that is? Face it, he's terrible. Any influence Allen has only makes it that much worse. The guy had a terrible defense when he was with Denver and somehow got hired as the Raiders head coach because, well... They're the Raiders. The whole defensive staff is stale.