Really?
The 3-4 in Dallas produced the single greatest pass rusher of this generation, two more Pro Bowl LBs, an All-Pro nose tackle, and a slew of highly sought after defensive linemen.
The change back to a 4-3 ended the tenure of the previously mentioned greatest pass rusher, exposed one of those Pro Bowl LBs to increased injuries, produced two of the worst defenses in franchise/NFL history, and set us on a 4 year quest to find down lineman that can consistently get to the QB while playing with their hand in the dirt. It put us in such dire straights that we were forced to assume tremendous risk in signing the most despised player in the league.
Our expectations are so low that we're thrilled if get a single sack in the 4th quarter and/or generate a single turnover during the course of the game, but the 3-4 defense was the problem?