Something I would be very hype about is the implementation of two classes in WoW:
The Witch class for Alliance, uniquely accessible for Kul Tirans, Humans and Worgens. A class based on the Drust magic, dark and ominous. Inspired by all the lore and visual surrounding Drustvar, Drust, Thros, and a little pinch of Harvest-witches.
The Witch-doctor class for Horde, uniquely accessible for Trolls (Darkspear and Zandalari). A class based on troll dark magic, voodoo and mojo. Inspiration can be taken from all sources of troll lore and maybe a pinch of the witch-doctor class from Diablo III.
Feel free to imagine different specs and spells name and expand on the idea.
Good day all !