There is a difference. However, I'm not convinced that it will cost velocity.
Not sure what you mean here. How should one go into the landing?
No, but Dr. Marshall's approach does take into account the physiology of the body. The traditional pitching motion doesn't, which is why half of professional pitchers experience serious shoulder and elbow problems. I think it's worth at least trying to improve upon that injury ratio.
Dr. Marshall does believe in external rotation (but he doesn't believe in scapular loading). You don't have to scap load in order to be externally rotated.
I disagree. There are a number of aspects of Dr. Marshall's ideas that I disagree with. I also disagree with his overall approach. I believe it is possible to morph a traditional pitcher to using a motion that incorporates some of Dr. Marshall's ideas.
Yes. Dr. Marshall believes the rotation of the hips, torso, and shoulders is critical. For one thing, that is why he beliefs pitchers should take shorter strides.