This would actually be a good feature request for a future update/version of AS Pro. I think color coded bones would be a great idea. Maybe even something like Final Cut Pro "labels" that have a certain color and you can put a label to it like "control bone", "hold bone", "rotation bone" and such. That way you can tell right away what each bone in the rig is used for...this would be especially helpful in a production environment so the animator(s) would know where the control and hold bones are versus actual rotating bones in the rig.