Currently little to no details have been revealed regarding the Warhammer 40,000 MMO. however, for the sake of a franchise where small arms fire is important I severely hope that it has little in common with WoW, as WoW is a PvE (Player versus Environment) based game. However it has been stated that all races important to the lore and to the players will be present in the game.
Aerith/Aeris Gainsborough: “The current system of servitude is barbaric and inadequate for today's generation. We appeal to the leaders of both the Imperium and the Coalition of Hateful Assholes and Organised Sin to seek to change this for the betterment of all its citizens”
Lorgar: “Guess there was one plot thread we forgot to erase ...” Mortarion nods in agreement, while Ahriman looks on suspiciously.
Aerith/Aeris Gainsborough: “We feel trapped, we feel oppressed. And we urge our governments to release us from these metal boxes-”
Lorgar: “Oh shi-”
Firraveus Carron: Leaping to his feet. “METAL BOXES?!?METAL BOXES!!!THEY RIDE IN METAL BOXES!!!”
All credit goes to Lastie on Warseer, for writing Primarchs (available in a 647 page Microsoft Word document)