Actually, I was wrong, you only have 8 dragons with devour. Meaning 85% chance that you will already have at least 1 on turn 5. 56% chance to have 2 on turn 6. Not so great. Having 3
Sarkhans Triumph brings the probability of having 2 dragons at turn 6 to 75%.
Maybe also take out Increasing Vengance altogether since Krenko does that better.
With 1 less Sarkhans and 4 less Increasing Vengance I would put in 3 Krenko and 2 Brightstone.
My two cents. Not an expert in any case.