Yeah, but it has 4 health. And usually you have to whirlwind to make it good, so it's 3 health ... and now we are looking at a card that needs whirl and charge and that's 3 cards for at least 8 mana and for 8 mana there are some real game makers for just 1 card.
tl;dr I have never seen berserker to do anything amazing. It's eat one kill small minion card. That's not op ... that's 1for1. It's good, but something to fear ? I usually just go ... berserker, attack it with minion and weapon. Now it's dead. Really strong card ... not.