Blizzard have introduced controversial ''personal'' loot for dungeons in patch 7.3.5 that essentially prevented transmog hunters from obtaining skins not linked to your character's class. In other news, there will also be frog mounts.
Personal loot sparked a minor fan riot on Blizzard's forums, reddit and pretty much any other place where players could complain about not being able to acquire new transmogs anymore. Blizzard took note and announced the issue will be fixed with Battle for Azeroth. Instances will feature a ''legacy loot'' system that will allow loot not meant for your class to drop. In order for a dungeon or a raid to qualify for the legacy loot system, it will have to be 10 levels lower than your character.
Since transmog hunters farmed older and easy to solo dungeons anyway, this system will be the best of both worlds where players will only get gear for their class where it's still meaningful for progression, and eye candy will drop where stats don't matter. This sounds like a match made in heaven, with Blizzard blessing everyone with their wonderful updates except for one tiny detail. Battle for Azeroth is half a year away, so this update will be anything but timely.
On the more positive side, legacy dungeons and raids will drop enough loot for 5 or 20 players, respectively, even if you solo them. That should make transmog hunting much faster and less of a chore. A full rundown can be found on the game's forums.
World of Warcraft: Battle for Azeroth will also include new mounts, just like each new content pack before and this time there will be frog themed mounts.
If you're not a frog person and like the robust, more serious-looking Proto Drakes instead, Battle of Azeroth will have those as well with a heavily armoured version this time. However, the only ones revealed so far are rewards from future PvP seasons so you might want to brush up on your Arena skills.