Okay, so this is a short OP, but..
Is there any real technological limitation that keeps Blizzard devs from importing some Heroes of the Storm models into World of Warcraft? Not all, of course, but looking at characters like Brightwing and Stitches, can't they just implement those in WoW? I mean, they're higher quality than their current in-game counterparts, as abominations, faerie dragons and crypt lords are as old as Classic.
Brightwing
Stitches
Anub'Arak
Now some models are too LQ to fit, like most humanoid ones (Jaina, Tyrande, Sylvanas), but wouldn't WoW gain from at least those three? They likely have a lot of elaborate animations too. If anything, at least the Faerie Dragon would make a good fit for a new battle pet.