After watching a portion of the video I think John isn't a punch stroker, it depends on the shot whether or whether not he bring his shaft back in the final stroke, sometimes he does and other times he doesn't. As I said depending on the shot.
Another thing that I noted which is kinda funny, when he becomes in the zoon his tongue goes out as he strokes the balls and to the side, I know that has nothing to do with anything but I just though it's funny that his tongue comes out to the side of his mouth and he bites on it, anyone else noticed this?

Plus I've seen other pro's that do this, Darren Appleton as he strokes the ball his tongue comes out but in the middle and he bites it.
I don't know whats the tongue deal here, but I know for a fact that Darren was called on it one time and he wanted to get rid of this habit, then his game dropped a considerable amount in level, a few weeks later he went back to biting his tongue, I know its weird subject but I swear these stuff happen and some peeps I think will lose their game if they stop doing these habits.