I think your dipping back is a bit extreme but if it works, hey.
On your back leg, your losing torsion. Basically your knee is kind on the inside, more internally rotated than externally. The reason you want to maintain torsion is because, whenever you externally rotate, the reaction is internal rotation of the drive leg, which is a huge factor in hip to shoulder separation. If it's already internally rotated, the hip rotation isn't as much