As I have said in multiple threads discussing this topic, I disapprove of making these weapons warglaives exclusive to the Demon Hunters.
I also disapprove of making them generic melee weapons.
The Warglaives used by Demon Hunters and Wardens are melee weapons. The Glaives used by Huntresses, Spellbreakers, and Glaive Throwers are ranged weapons (and basically giant shuriken). These are very different.
What I would like them to do is restore the Thrown weapon as a weapon type. It has been absent in game since before the great weapon restructuring which allowed Bows and Guns to be primary weapons. Why not bring them back?
Warriors, Rogues, Monks, Hunters, Demon Hunters, and maybe a few more classes could all have specs and builds centered around Throwing weapons.
The chakrams from Kingdom of Amalur give a good idea of how I see them playing as a third spec for Demon Hunters, or if Wardens or Spellbreakers ever become a player class. Ranged damage mixed with spellwork and a heavy focus on AOE and mobility.
But it should be fairly easy to see how specs could be built off of this weapon type that would work well to give Warriors, Rogues, and Monks ranged DPS specs, as well as more specs for other classes.
Yes and no. It’s implied that SOMETHING happens to them during the process, though they don’t get as big of a buff as Tyrande does.
Beyond that? We have no clue. As far as I can tell, the actual cutscene of Tyrande getting imbued with the power of Elune and whatever may come of it is still not up on the PTR, nor has it been shown to us yet. So for all we know Nathanos and his undead rogues throw a bunch of water balloons filled with black paint in our faces.