If you have the right players, the 3-4 is great. But the 3-4 is based on deception such that the offense never knows where the fourth rusher is coming from. In order to do that, you have to have multiple pass rushing threats from the LB position and your ILB must be able to play at either MLB or OLB. The main "problem" that we had when running the 3-4 was DeMarcus Ware. When you have him on your team, the offensive pretty much knows where that fourth rusher is coming from. Find 94, that is where the fourth guy is. LOL If Dallas were to go back to a 3-4 tomorrow, we would have the same "problem" with Parsons. Also, Tank might hold up as a 3-4 end or he might not. Same for Odighizuwa. Both are a little light for that position. And we have zero candidates for Nose Tackle in a 3-4.