I'm not saying DCs should only load the box but I'd skew heavily to stop the run for the first half of the game to see if I could keep the pressure on Carr. He's shown he can throw the ball but he hasn't had to carry a team and he hasn't had to play from behind and make clutch throws. If I'm a DC, I do everything I can to stop ND's run game and see if Carr can beat my team. Then, if he proves he can do it under pressure, then I'd change it up.
I'd also mix in a lot of zone, robber, nickel, cover 2, dime. Cover 3 can allow teams to cheat a little and keep the LBs aggressive, maybe. Ultimately, I want to see which teams can present one thing pre-snap and something else post-snap, and I want to see how Carr adjusts to that.