Hello Mig,
Some of those issues sound like the way that ppl are setting up their stances in th first place, and for what reason...
"Bow and Arrow" step will lack leverage and power if one steps directly into it from a natural stance (shoulder width), ok...
Therefore, I think most of us learned to enter from an offset, side-body stance (Side Horse)...
Having the weight in one's front foot, we have a balanced, grounded framework we can enter with explosively, with all of the weight in our own front hand...
Planting the front foot at an appropriately inturned angle, we may trap his foot or collide with his shin at the same instant as our hand contacts, taking his root and putting him under our bridgehand control...
Regardless, once the front foot plants from the sidehorse entry, it doesn't move again until after the rear hand contacts by means of the bow step shift...
This allows us to keep our weight on the guy, and maintain our rooted control, momentarily, just for the duration of that particular section of leverage expression...
Moving this way, you will hurt his leg, and he won't be able to stop your hands...
(Unless he's doing th same thing YOU are, of course!)
Locking the back leg is just for slow motion training...
ALWAYS "save an inch", just like in punching and kicking. Changes are faster, More powerful structure, and less likely to suffer a joint injury, either from taking an impact at that point, or from one's very training, repetitions adding up over time to aggravate then possibly damage the joint beyond repair...
Best,
Mike