Hearthpwn

A good card if you have any presence, so you can mop up if it goes wrong, or just doesn't go quite right enough. Might make Spellpower Shaman a thing but I doubt it, there's just no good examples of spellpower really working in a mid-range deck, though it's a certain boon to a possible Miracle Malygos, but then does Shaman have the card draw to base a whole deck around a single Legendary draw?

Another angle is that this is another good/playable Overload card, so more potential buffing for Unbound Elemental, which already gets some play. What I'd really like to see is an Overload-related Mech minion, so we have something else to buff with this effect. Maybe a Battlecry that buffs for every Overload card played that turn, or even has health equal to all the overload mana accrued that turn.