This is a midrange deck. Basically there are two win conditions, either you power your opponent down through minions+heal or you get out Velen with a Mind Blast and/or Holy Smite. If he lives the turn your opponent is most certainly dead. If not, you are still probably in a good position. Save your Mind Blasts for Velen unless you can use them for lethal without him. 2 Mind Blasts plus Holy Fire is 15 damage for 10 mana. Better than savage roar or pyroblast, although it does take 3 cards to pull off.

On the cheap, you can replace Sylvanas and Black Knight with any appropriate high level/high value cards. Sludge Belcher, Boulderfist Ogre, Sunwalker, Spectral Knight, etc. The deck is centered around Velen, however, so there is no substitute for him outside of maybe a Malygos, but that isn't going to be easy to play.

If you're facing more midrange/control decks than agro, switch out the senjin's for yetis.