Clarification on bonus rolls for mounts, pets, and heirlooms
Ever wondered if using a bonus roll on a particular boss would actually grant you another chance at a mount or pet? Item and Rewards Designer Owen Landgren took to Twitter to clarify where bonus rolls do and do not work for specific items.
Bonus rolls do not work for Garrosh heirloom weapons. These only have a random chance to drop into your bags on each kill in flex, normal, or heroic.
Sha of Anger, Galleon, Nalak, and Oondasta mounts can be obtained with a bonus roll.
Raid mounts, such as the Reins of the Astral Cloud Serpent, cannot be obtained with a bonus roll.
Kor'kron Shaman's Treasure (shaman transmog gear) cannot be won with a bonus roll.
Battle pets which drop from Siege of Orgrimmar bosses can be won with a bonus roll and they do not affect your chance at getting regular loot (winning a pet will not replace potential loot you could have won). However, the Quivering Blob from Throne of Thunder can only be won with a bonus roll on LFR difficulty and not on normal or heroic.
I'll admit I was surprised to learn that the Garrosh weapons could not be won with a bonus roll. Blizzard's reasoning is they do not want you choosing between account-wide and character-level power when you bonus roll. Hopefully these clarifications will help you better spend your precious bonus rolls.