Hey, I think I noticed a bit of a symmetric pattern between most of the classes now. For that you need to keep this in mind: World of Warcraft Cosmology Chart in Color - Wowhead News. With the Drust, Naaru, and Sargeras it seems like every cosmic force in the story are two sides of the same coin. This is why this symmetry now becomes noticeable with the classes and hero specs seemingly. I’m not 100% sure though, but it seems logical:
Chaos - Order: Demon Hunter (purely chaotic), Warrior (mixed), Mage (purely arcane)
Death - Life: Death Knight (purely death), Hunter (mixed, Dark Ranger vs Sentinel), Druid (purely Life)
Void - Light: Speculative void class (purely void), Priests (mixed like the Naaru), Paladin (purely Light)
Regarding Dark Ranger and Sentinel I want to clarify, that Blizzard differentiates between the cosmic force and type of magic, so for example Lunar forces may be classified as “arcane damage”, but it’s from the Life-force. The shadow magic, that Dark Rangers use, is not from the Void, it’s from the Death. I know, incredibly confusing, but that weird distinction is done for gameplay reasons apparently.
Not all classes really fall into this pattern though, such as warlocks, shamans, and rogues, but some do. It’s also worth to mention, that this shift in world-building happened quite recently, so that’s also probably why there is this confusing naming-ambiguity between world building, and gameplay systems.