Hearthpwn

This is the deck I used to beat Heroic Vael. The strategy of this deck is swarming the board with low drops, notably taunts, to gain early board control and play as many cards as you can each turn. Starting with one drops is essential or else you lose board control and start burning cards.

I liked the priest class for this boss not only because of the great Divine Spirit + Inner Fire combo, but also the new Twilight Whelp which should always come onto the board as a 2/3 because of our Twilight Drake.

The Silences work great not only against his Twilight Drakes, but also on our Zombie Chows and Deathlords to counteract their drawbacks.

The Lightbombs are key in the mid to late game to clear his board and hopefully keep yours alive, hence the high hp creatures. Once you've stabilized, it's critical to close out the game quickly with Inner Fire or you'll probably die to fatigue. (I beat him with him taking fatigue damage, I would have died next turn).

Hope this steers you in the right direction if you want to try this version. Leave a thumbs up if these tips were helpful, good luck!

P.S. Make sure to check out my decklist for Heroic Razorgore: http://www.hearthpwn.com/decks/235035-brm-heroic-razorgore-the-untamed#c4

Additional bosses to come.