Now we go to my opinions and not the measured data, even of course that has something to do with measurements.
i think many players try to swing too much on line. They are pulling the handle toward the ball and try to come to the ball from straight line. It's great to hit it about from the straight line, but without trying to do so. Yep... sounds weird, but I'd like the club head arrive much inside and just reach the straight line just before impact. Maybe 2-3 inches before and by rotation. Let's say as much inside as possible relative to Your body and as straight as possible to the target line.
All good ball strikers I have measured drops their club head much behind their back and on the half way down, the shaft is about 90 degrees cross the target line. And from there they just drag the club face and the whole club around them. There isn't any move or pull toward the ball.
I think watching face on videos has made some bad to many golfers, because missing the depth of the movement You miss the most relevant thing. When watching 2D video from face on, the picture in peoples mind says the swing is around the horizontal axis. "Around the fixed hub" like Cochran & Stobbs told us at 60's. What will happen if You start to think it from the view that we don't normally see; from the top down? Quite soon You will notice You automatically drop the head more inside and You go more around. You don't try to do anything toward the target, You go low and left instead at impact. That will give You more shallow approach and hands more ahead of the face without big forward lean... damn I should make video some day about this
It's so complicated to explain by writing.
But as conclusion I think it's the mind set. To change something in Our swing, we first have to think it different way. Muscles newer accept to do something which is against our mind says.
About the force across the shaft I haven't have time to make it really clear to myself what it means, but from this point
the shaft turns about 180 degrees to the impact, and from top down view, thats quite pure circle from the club head. Most of the average players are pulling the handle toward the ball from this point and cutting inside of that circle, when these better players make it with rotation.
I hope I more cleared it out than confused... not really sure myself