Xin's ult should be like Graves W for both Xin and the challenged oppenent inside the arena
By that I mean both Xin and anyone else inside the circle are blinded to the surroundings for its duration or until only Xin is inside (making is so he can't just blind himself). I don't think Xin is weak or anything, I just think this would be cool thematically and make for fun gameplay.