Carrier's hypothesis is interesting and well argued, but only time will tell if it stands up to further scrutiny. This is the scientific process. Yong, on the other hand, is just defending his own preconceptions. While I agree with him that the established theory of changing diet/changing dentition is very well supported, Carrier's theory doesn't necessarily contradict it. Both of these theories could have shaped the faces of our ancestors and, eventually, us.

I would love to see models testing how well the skulls of different human ancestors and humans themselves stand up to blunt blows, both head-on and oblique ones. It's possible that the skulls of modern humans, despite being more gracile, might perform surprisingly well thanks to the force-spreading properties of our parabolic dental arcades. i.e. If you hit a human in the side of the jaw you're hitting a self-buttressing arc of bone and teeth. If you hit the U-shaped jaw of an australopithecine on the side, you're hitting a straight wall.