Vol'jin got the Alliance to join the Horde. Best Warchief ever.
The thing I notice is every lore point that's ever discussed is what will [Horde lore figure X] do in [Event Y]
You literally never see any discussion asking what the Alliance lore figures will do in Siege of Orgrimmar. Because they've not been written in the build up for us to expect anything. They're just sorta......there.
/shrug
Looking forward to seeing the raid and ending cinematic. I have mostly avoided info on the raid, I just know which characters make appearances.