Patch 7.2 is closing in! You can now download it in the background downloader and that means it will most likely arrive within a week or two.
There are many new things coming with this major update patch. I highly recommend checking out a summary from one of the big WoW news pages.
In terms of pet battles, a good number of new pets are coming, but also new world quest tamers and a whole new pet battle dungeon.
As promised, Xu-Fu got you covered :-)
Below is an overview and links to the respective guides:
Pet Battle Dungeon "Wailing Critters"
Challenge Mode Guide
New World Quests
Illidari Master Sissix
Illidari Master Madam Viciosa
Illidari Master Nameless Mystic