Blazindragon on 28. Jan. 2018.
It's going to be 4 with the preorder (Highmountain, Lightforged, Nightborne and Void Elf) and there will be 4 at launch (Darkiron, Dragonmaw, Kul'Tiran and Zandalari Troll) I'm calling it now!!
BTW I chose Dragonmaw due to the fact they would have unique armor if the old races got heritage armor, awesome dragon style racials and they need to escape the big Alliance wave of enemies coming up to Lordaeron