Have you considered adding
splendid agony to this deck? It lets you place -1/-1 counters on creatures and can be an effective kill spell for this deck. Also
faith of the devoted may be a better choice for you than
drake haven. Reason being is that taking the opponent's life puts them on a tighter edge than simply having creatures that they could possibly board wipe. That's just my opinion on that one, what do you think?