control which is 10 mana to kill AND gain a super powerful minion.
Paladin has a 1 mana polymorph.
Mage has polymorph.
Druid has only 2 cards to remove a minion with over 5 hp, and not without throwing the game at the same time. Using only 1 mana doesn't even matter. If it cost 8 mana and still gave 1 card it would be better.
Druid is so obviously underpowered right now Blizzard must have never tried him.