Can we please stop using absolutes in our title if there's no evidence from the horses mouth to support it.
5 Reasons why Artificer COULD be the next class in WoW.
I like the concept of an "artificer" who's trade is magical contraptions and constructs. It could fit in WoW but I don't really see how they'd be "Back-populated" in a lore friendly way. "Monks" existed in the ranks of the scarlet monastery long before pandaria. "Tinkers" and "WC3-Esque-Demon Hunters" Exist throughout the world today. (Gnomregan; Ashazara/Darkshore, outland.) Coming up with something out of the blue either means it has to be a hero class, or they need to retcon existing lore to give them a logical presence in Azeroth.
The second problem is that the varying races of azeroth have very different styles of "technology", and you're either going to have a freak of nature using a mish-mash of different races of technology, or you've got both factions using a similar style of tech, which basically needs another shoe-in for the lore as to "why" they're doing it this way instead of the way that trolls/orcs/night elves/draenei/undead/humans/dwarves/gnomes/etc do it.