Defensive coordinator's job is to put guys in position to make plays. At that point it's up to the players to make the play. Here's a quote from Pickett on the Eagles loss:
"I think we messed up a couple things, but other than that it felt like a normal game out there," Pickett said. "I don't think it was scheme-related...On all those runs, if you watch them, somebody at some point had a shot to get (McCoy) down for maybe a 3- or 2-yard gain. Even with eight in the box, you got to make a tackle."
So why is it Capers fault? I get that it's easier to blame the coach than the players because that means a quick fix is possible. The problem though is clearly the players. Capers can't actually go out there and make the interception against Jackson. He has to rely on Burnett and Williams not stumbling all over themselves and tipping it to Jackson. Capers can't go out there and strap himself to CM3's right side to give Matthews a right hand that can actually do something (btw, I get that Matthews is great and all, but he was completely ineffective yesterday, he shouldn't have been in the game).