WCY and LCY were relatively equal in martial arts, although WCY could have surpassed her in his later years. However, LCY created a set of martial arts that even WCY cannot fully counter. Her greatest accomplisment is the sword play from her manual. After learning L/R technique, XLN is able to use two sword simultaneously, which may prove more powerful then two person as she can better harmonize the techniques then two indivdual can. So if she uses that swordplay against WCY, would even him have a problem dealing with it?