The Empire and the Britonians are the only human races in warhammer. I know they are humans that take place in the medieval era, but why not add a little Greek mythology.
Warhammer would do good to have a race that was only as greek mythology, for example.
Core can include your regular infantry, hoplites and bowmen.
Specials can include Spartans
Rares, can include, Medusa's, cyclopes
The magic can be like priests, and you can worship one of gods like Zeus or Apollo and call upon the God powers.
A war machine can be like the giant horse gift of Troy. You can load it up with infantry and they are protected inside. Wheel it up behind enemy lines and let them out.
But if we cant have a Greek mythology race. It would be nice to add a few examples of it to the empire. Like Medusa's and Cyclopes, or the war machine of troy. This would give some more power to the empire.