The Ziggy-KVN defense was so good in large part because those two were so good at getting after the QB. Teams couldn't just focus on stopping one of them (like they can do with Bronson). You could split them up or double them up and odds were good one of them was getting pressure.

BYU's best defenses came when pressuring the QB came without having to bring the blitzing LB. Like TCU or any good defense. If you can get pressure w/ four defenders - whether in a 3-4 or 4-3 - you're going to be a very good defense.