>>> Thanks Jack
Actually that was my point that the lead leg straightening helps the hips to rotate but in the case of bug squishing with the back foot it makes the hips rotate too much or too soon.
I am an advacator of NO BUG SQUISHING and want more drive by the back leg. I want my students to be in control of their shoulders so that they can help to control when they snap their wrists. (I would assume that is your BHT) Circular hand path is created by rotating the shoulders with the hands staying connected to the them until it is time to snap the wrists. That is a whole other conversation.
Do you find that some players tend to continue to rotate their lead foot too far past the 45 degree angle that you are looking for when they start closed and pivot open. I prefer my students to stride to their instep with their foot at a 45 degree angle so that then the heel drop is striaght down. This would be the reason for their back foot to initiate the rotation. <<<
I have not noticed a problem with my students over-rotating the lead-foot during heel-drop if they land closed. The main problem is with batters that stride to an open foot. This too often leads the lead shoulder prematurely leaking open (loss of stretch). As you point out, to stay connected, the batter must keep the lead-side muscles stretched during initiation and rotation.
You state, "I want my students to be in control of their shoulders so that they can help to control when they snap their wrists" -- Since you added your comment on "BHT," I think we are on the same page. However, the term "Wrist snap" always raises a 'red flag' with me. Below is a post from the Archives I wrote on this subject.