Hearthpwn

Youthful Brewmaster wants to target Kazakus, Stonehill Defender, Elise the Trailblazer, or Curious Glimmerroot, but could be used later in the game to act as a full heal on a minion after a trade (as well as an easy way to feed a bonus card play for Shadowreaper Anduin).

I'm on the fence about Spirit Lash and Prophet Velen. Velen can be a very powerful closer after you've played Raza the Chained and Shadowreaper Anduin, but he is very slow. Similarly, Spirit Lash can be very useful, but without spell damage to improve it, it can be too little to matter.

I've played a bit with the Archbishop Benedictus/Hemet, Jungle Hunter combo version of this deck. It's not a totally natural fit - obviously you can't play Benedictus before Raza, and replacing your low cost cards with your opponent's deck may mean you get fewer usages of the Voidform hero power. That said, I think Archbishop Benedictus can serve to protect you from some of the major mill-style effects you can get from the Death Knight cards (namely Doom Pact and Army of the Dead, both of which can easily take five or more cards off the top of your deck). So far I haven't had any major issues dealing with fatigue, and haven't noticed that the combo is all that helpful in most games, so he remains absent.