So Total War Warhammer will have four races. Humans(Empire), Dwarves, Vampire Counts and Greenskins. But does that mean there will be only four playable factions or are the four races representing groups of factions. Since Greenskins, Dwarves and the Empire aren't singular factions or countries. The Empire is divided into the various Grand Counties, the Dwarves are divided into kingdoms that swear allegiance to the High King and the Greenskins are divided into various clans. So there could be several playable factions instead of just four. The Greenskins would be interesting like this. The player would have to fight other Greenskin clans in order to form a larger Waaagh!!!! Conquering other clans would add more units to the player's roster as well as their armies(that aren't already destroyed).
Empire: Reikland, Averland, Wissenland, Stirland, Ostermark, Talabecland, Ostland, Hochland, Middenland and Nordland
Dwarves(Atleast the ones close to the Empire): Karak Norn, Karak Hirn, Karak Kadrin and Zhufbar
Greenskins(Tribes close to or inside the Empire): Red Eye Mountain, Red Face Goblins, Spiderclaw Tribe, Ironclaw Tribe and etc
Vampire Counts: Von Casteins of Sylvania