This is similar to other versions of the Dragon Priest that are going around. Notably differences include the lack of Velan's Chosen, and Nefarian (I don't have Ysera). Because of Nefarian, I swapped in Boom as well to provide more than one BGH target.
The important part here is the mulligan. If you can manage to get out an early taunt and play on tempo, you will generally win. I added a Lightbomb to help re-stabilize if I'm off tempo, but many players are running fine without it.