Hearthpwn

Mage deck that aims to abuse hero power synergies with the cheap hero power thanks to Genn Greymane, particularly with Coldarra Drake, who lets you get many inspire triggers in a single turn, deal lots of efficient damage with Fallen Hero, freeze multiple enemies with Ice Walker, etc.

With the even-only restriction, Book of Specters is the best card draw available. Luckily, hero power synergy in mage naturally gives you quite a bit of potential to interact with your opponent's board without needing to use many spells. Echo of Medivh is a card with a very high value ceiling, especially in a minion-heavy deck like this, allowing you to generate plenty of extra threats in slower matchups. Especially great with Frost Giant!

Emperor Thaurissan is often the most important card you can draw, as he allows you to abuse the hero power synergies much harder than would otherwise be possible by allowing you to play the relevant combinations of minions multiple turns earlier, or with multiple extra hero powers, or just a larger combination of minions at once! I think it's probably correct to keep him against any class that's unlikely to kill you before turn 7.

Spirit of the Dragonhawk is a welcome addition to the archetype, but unfortunately the rest of the new hero power synergy cards are odd-cost.