Play a dropback QB.
Everyone is playing the 3-4 to give you more pass coverage and that's understandible. Problem, you have too many QB's running the option and these DE's don't know what to do. I watched it all year with QB's juking DE's and cutting it up. If you want to know how to defend against it, go back and watch old 70's games when they ran the wishbone. Same type system where the QB could kill you by heading up field. Bond was the master at it, but he got hammered. I couldn't see Manziel taking the hits Bond did back then. You have to make someone commit and that would normally be the QB. It kills me to see these guys come down the line and not get hammered. They can't do this in the pro's because that's what will happen. That's why it's not run that much, up until this year, and watch what the D.C.'s will do with it over the off season. I would go to a 4-3 and make damn sure those ends kill the QB everytime. Let the QB beat you by throwing it, but make damn sure you hit him every play. Did anyone else want to see Manziel get clobbered this year? Same with Wallace. If he pitches it, make sure that you got great closing speed on your outside LB's and also your corners being able to break blocks. Again, go back and watch teams that shut down the wishbone and you'll have a start to your strategy.D@A nailed it. But a simplified answer is assignment football. The defensive end closes and takes the RB every time. It takes the human element of decision making and reacting out of it. Make the QB keep it every time and take hits. It's much easier to prepare for when you force the QB to keep it each time. Like I said, that's just simplified. It's not fool proof or anything close but that is what I've always heard.
Play a dropback QB.