Did you noticed those Gnomes in Island Expedition throwing bombs and stuff?
Well there you have the next class in WoW also line up perfectly as the next mail wearer which will be the next one to keep it balanced (only 2 class in wow wear mail).
All the AI bots in Island Expeditions are playable classes except those gnomes.
Yeah maybe. I was hoping for something more Ranger-y.
Tinkers are widely speculated, which I presume would be an engineering- inspired class, with bombs and turrets and other gadgets.
Which could be engineering as a profession. But Blizzard gutted professions a while ago.
Whatever the next class it needs to be non-melee with the exception of it having a tank spec. We are way too saturated with melee. That and it should be mail armor type, there still only two classes that use mail.