Bats are the mana dump, for this build, while pets hold mobs off and add some incremental damage. Gruesome feast will buff intelligence, and after it's buffed then it's time to re-summon; buffed pets will perform better. Hex provides at least a little direct CC and hedge magic provides some healing.
Zombie handler could be a very attractive choice for a passive. But, it's difficult to give up on the ones that were chosen.