Riot Blade does the same damage (maybe a little bit more) as circle slash II, costs twice as much TP and prevents you from using any WS for 30 seconds, making it impossible to hold agro on that enemy after you use it. How is this worth it at all? If Riot Blade made the enemy not able to use WS's then I would totally understand, however for a gladiator to not be able to use WS is just dumb.