This card will single handedly be the death of aggro. A 13 hp taunt with a drawback of Flame Imp on turn 5 (that is also netural btw)... how do you get through that? And yes, you might say that it has about the same effect as Viodlord but Voidlord needs to be ceated out to come out before turn 9 and it is also a class card. Wtf were blizzard thinking.
It's not the flame imp effect, I actually checked and if it was like flame imp it would say it deals damage to your hero. it loses HP based on opponent's handsize.
If it were a warlock card I would agree, but classes that don't use HP as a resource can make an exception for this card because its mostly going to be classes like warrior, druid and priest that would be likely to use this and they don't mind taking some damage to get board control.