I played demolisher in zoo/early board control warlock before I had a lot of cards, the 4 toughness makes it hard to remove and when buffed with a doa even harder. Its amazing when it hits the right target, but the rng is its downside. Although, I bet you it would be pretty good if you're seeing a lot of zoo/hunter since they tend to play a lot of 1/2 health minions making it easier to hit a good target. It would also be a way to remove hunter minions when they have snake trap up.
Golden cards baffle me, I have so few, but I've somehow managed to get things like 3 golden frothing berserkers, 3 golden kidnappers.