Well in my opinion it is kind of useless... low dmg and spell disruption doesnt work on bosses...i believe Zwieb said that the new spell in 1.1j would be most definite for the class but it is realy not giving the feeling that i have assasin that have some use in team fights.It is ok when stun dont work on bosses but i think that at least skill disruption should be allowed to be used on them...or at least buff the dmg.Assasin have some nice skills that help him solo creeps but in teamfights it is kind of useless.So if spell interupt was working on bosses from new skill this would definitly make the assasin a valuable member of dungeon groups.