Mike, I was not talking about the B skip, we were talking about the same drill. I still feel it's not a good drill, but I guess we can agree to disagree.
Maybe, I can explain myself a little better to give you an idea of where I am comming from. I am a big believer that everything happens off the ground (knee-lift is a product of force application) and that front side mechanics does not need to be coached(it's reflexive).
I don't see how an athlete can perform a B drill without lifting the legs via hip flexors. This means the drill is started with wrong mechanics and therefore can only end wrong. However, the A drill is different, there is only one focus,pushing the knees up and the time frame of the drill allows for this. I am yet to see an athlete push his knees up and then reverse it fast enough to cause the lower leg to unfold at normal drill(walking) pace. Maybe, the B-runs or straight leg bounding is the answer.