Being mobile is not always the best way to play either. A good camper, a smart camper can easily deal with a headless rusher. Only the smart rusher/flanker is the problem for the average camper. I have played both sides of the fence and neither is really better than the other depending upon the players and the tactics they can employ to that particular means. A smart defensive team can easily deal with a group of rushers with proper communication. It would take a team of smart flankers to deal with that team, but not often does both teams really come against the opposiste that is really good at doing what they do.
I usedf to play with a group of players on BO2 and we could easily lock down slums against any rusher/mobile team. Once setup they had no chance except a lucky spawn to get behind us.