I like what Mankin has to say about the hip/shoulder/bat lag. He suggested that you focus on the barrel arcing throughout the entire swing/arc, supplying energy to the barrel or TTB immediately. Although, there is some natural lag in overcoming a body at rest. So the barrel is at rest (somewhat) and the act of overcoming this create lag between the hip/shoulder/barrel.
I wasn’t around when Mankin was en vogue so I can’t speak on his theories. But I am of the belief that the hands control the swing from the get go, which starts the sequence and finishes the sequence. While a leveraging core aided by dynamic balance of the COM makes for an elite level swing pattern.
Is that inline with Mankins beliefs?