Moorish and Lizardman races for X-pack
Since the vanilla game is taking place on a continent with a temperate climate, I think the X-pack should introduce some new lands with warmer climates such as desert, savanna, and jungle. I have a couple of race ideas for such an expansion:
Although really the same species as Men, the Moors are often considered a distinct race due to their black skin and kinky hair. They are native to Mythador's savanna and desert regions. For the most part, the Moors play similarly to Men, but their infantry and archers tend to move faster and have less body armor. Also, the Moors have domesticated a number of savanna animals such as zebras, rhinos, and elephants for use in battle.
These intelligent, carnivorous lizards have constructed their civilization in the tropical jungles. They get most of their food from hunting, but can also sacrifice their own units, or captured enemy units, to get food. Sacrifice is also a way for them to get Influence. The Lizardmen have tamed a variety of large reptiles for battle mounts, including the flying wyvern, but these are more expensive than the cavarly units of Men and Moors. Lizardmen can also slowly heal themselves.