I have a suggestion for different tribes. That would be unique troops for each tribe, for example: A samurai unit for the Xin Xi, a Sword and Shield unit for the Imperius, or a Crossbow unit for the Hoodrick. These troops would have different strengths and eaknesses or even special abilities, similar to how the rider has their escape ability. The Samurai could deal more damage against the Hoodrick's  Crossbow units, but would struggle against the Imperius's Sword and Shield units. Also special abilities could be included, for example, the Crossbow unit could have an ability where if they shoot a target, that target would be wounded, only being able to move half as much as they could the minimum being 1 tile. There would be ways to counter this, such as the mind bender being able to remove all negative effects or being able to heal units (one or the other so that mind benders don't become too strong) so that it's not impossible for one tribe to defeat another. The main reason I suggest this is because, aside from the unique starts each tribe has and the special tribes, most of the tribes end up becoming very similar to one another.