Mike, who is talking about shoulder rotating swing ? Are you using Rich's definition of 2 legged hitting (weight shifting across the pelvis to the lead leg) ? The core pattern doesn't compromise the rear leg/hip relationship while getting fyb.
the question was about hitting the inside pitch. Yes I was but you explanation and video makes sense too. A lot of hitters rotate the rear hip causing trouble keeping the front shoulder from flying out taking the barrel in a circular path.