Barov is good card indeed, I have no disagreement. But, against aggro warpath is better because its more versatile. Since most of the minions are 1-2 health in aggro decks its easier to execute. Plus you don't need to wait for him to die for cleaning the board. If you want an instant clean, you will have to spend a spell to kill him i.e. shield slam, if you wait a turn, he may be silenced or cc'ed. On the other hand, Barov is very good for cleaning big health minions if you can manage to kill him. But in the aggro decks nearly no minions more than 3 health.
I agree with you on Ysera btw, you need to have 6 cards most at hand to play her.