Kabal courier is pretty good. If control hunter is a thing, this card might be better than it. It's basically a guaranteed good draw and doesn't even draw the card from your deck, so you can theoretically draw it a second time. Good for legendary minions, now hunter just needs a good legendary minion you actually want two of in a deck.
Its probably too slow for aggro, but in a slower deck it could definitely see play.
I'm glad this got put in hunter. Hunter has the best access to spells that produce minions, so you can use a majority of those, and choose carefully which minions you want In your deck to have a better chance at them.