I think game would be much more interesting, if every(!!!) race would have got some unique feature(s). It would develop new different strategies and game would never become boring and too simple(IMO it will pretty soon).
I would suggest the following features:
1)Race get increased chance of 1st go
2)Race can hold 9 or 10 units in one stack
3)Race can move units within its own lands(for example only 1 unit per turn so that it doesn't become unbalanced)
4)Races hate each other: f. ex elves get 10% attack bonus against vampires or smth like that
5)Race can strike from distance(for example 3 times a game)
and so on...
Also the main idea is to make each race really unique and not just name and the symbol.
Surely such innovations would firstly bring a total disbalance but it could be fixed after some time playing and experimenting.