>>> Wait, you forgot football throws, football hits, volleyball serves and spikes, tennis and ping pong? Discus?? Swimming is even rotational. Gymnastics? Try doing beam without a ground up approach. It all involves either a true kinetic link or super strong core muscles. Soccer you say? Try moving the striking leg at the same time as the plant leg. Gotta have SEPARATION. It's what makes limbs go Fast! <<<
Since the greatest amount of load (resistance to rotation) is located at the top of the kinetic chain during the swing, I agree that separation would naturally occur between the segments. However, as the posts from the Archives below explains, batter induced separation can be counterproductive.
Opening of the hips
(Video) -- Bonds hip/shoulder comparison