I'm fairly certain that after she was transformed she lost any connection with the Burning Legion. Plus, the Old Gods wouldn't deal with the Legion either. They want their world, they don't want it destroyed, which is what the Legion ultimately wants. There's the possibility of them tricking them, but I doubt that an Old God servant would be their harbinger. The Old Gods work in much less direct ways than that. They prefer manipulation.
Should probably get those glasses checked mate... the only zone that actually focused on pandaren would be Valley of the Four Winds. Every other zone's about the sha, the Alliance / Horde, the yaungol, the mogu, or the mantid. Doesn't seem much like it's about the pandaren :P
Yeah pandaren are in all these zones, but they aren't the focus (IE those zones aren't about pandaren). You can replace the pandaren with any other race that's allied with the players and the plot wouldn't change aside from replacing the pandaren with these guys. The plot's made revolving around the conflict (as most plots are), and the pandaren are not such.
You also need your glasses checked, sir!
Demon hunters in warcraft wouldn't be ranged... they carry around giant warglaives, it's hard for them to do stuff at ranged
Plus that's how they were portrayed in the RPG and in encounters during TBC... It'd be a pretty weird curveball for them to suddenly have the capability to be ranged fighters.
And I always felt like they dropped the ball on mail. Only the wealthiest or highest ranked soldiers wore plate. I always felt like mail on a non-tank warrior or paladin (since tanks always seemed like they'd fit that "CO" position, to me) would be appropriate.