Black Ice

In the previous Revan expansion, we had a whole zoo of creatures, but it didn't really add much variety to the gameplay. And even characters of the same race can be very different. As for combat effectiveness, that's not the most important thing for an interesting game. For example, Nebk has a rather interesting character, but he's not very useful in combat. You could create an Atroxian who deals 100-200 damage to most enemies each turn (ignoring armor), but it would be a rather boring character.