Do you have an example of a pitcher who has that issue? I'm curious to see an example of a pitcher with that issue.
Throughout the process of changing my arm action and overall mechanics, I was pretty consistently told that I have good internal rotation, when my external rotation was poor. So that is something I have little to no focus on that part of my mechanics. I also did very little research on internal research in general, so I am not very knowledgeable about the issues associated with pitcher lacking it.