Too many sins in game to remove it now. But I've always felt like the addition of another melee class always throws things out of balance. Warriors are supposed to be the tanking heavy hitting characters. With wizards being the glass cannons/AOE class, and Taoists being necessary for boss hunts.
With sins in the game, they either have to take away from other classes, or they have to have game breaking mechanics (in my opinion) like super speed and invisibility. I mean, they literally have speed hacks. Before this server, it had been so long since I played mir that the last time I saw someone running that fast they were banned for speed hacking.
Sins have to stay at this point, but I would at least like to see them not having game breaking abilities like super speed and invisibility.