They would be pretty good - not amazing but pretty good - if not for the fact that Hearthstone is utterly and completely dominated by aggro, the bane of any slightly slower deck. The aggro-bloated meta fucks the game up so much. When 90% of the decks you run into are face, zoo or mech, you can't really play the dragon decks. The game's design is extremely flawed in this regard as it overwhelmingly encourages playing aggro, and therefore renders unviable any deck that's a bit disadvantaged against aggro.