to me the photos are self explaining
if the action back pleat is close to the shoulder/sleeve seam keep the yoke because that action back is not that useful to begin with (probably worth more of an expansion panel when you're layering clothes than a real shoulder movement), however if action back is further away from the shoulder and more to the center between your neck and shoulder which is a real useful action back then no yoke
if the action back pleat is close to the shoulder/sleeve seam keep the yoke because that action back is not that useful to begin with (probably worth more of an expansion panel when you're layering clothes than a real shoulder movement), however if action back is further away from the shoulder and more to the center between your neck and shoulder which is a real useful action back then no yoke