Inability to get a yard when you really need it is a hallmark of the West Coast Offense and the Zone Blocking Scheme. The former doesn't typically commit to the run, and will more likely rely on a quick pass - it has been a hallmark of the Andy Reid offenses, which Harbs is most familiar with. I'm generally a fan of zone blocking in the right scheme, but it is a very reactive, east-west approach: O-lineman steps in a direction, and doesn't really know who he is going to block until the defense slants, bulls, or stunts.
Our offense is a hybrid of West Coast and Zone Blocking. That yard will continue to be hard to come by. That's why we need a bigger center. When in doubt, QB sneak and pray.
Seems the Ravens have mastered the forward pass behind the line of scrimmage that loses yardage. The good news for Joe is that it pads his pass completion stats.