I think the people who thought Zach would suck because of the impression(For whatever reason) that linebackers need to take on linemen more often in the 3-4... Which isnt true. The scheme puts more big bodies between him and the O-line. One of them may stunt every once and a while, but he'll still have the same two-gap run defenders infront of him.
What has really impressed me about Zach was his blitzing. I figured he was going to pretty much play shallow zones while the other linebackers blitzed, and that if he was asked to do anything more then a rare delayed blitz he would get gummed up in the center.
But no... Every time he blitzes, he gets good penetration. He doesnt allow the man blocking him to anchor, and he keeps moving upfield.