This is admittedly a more food-for-thought suggestion, and is based primarily on my desire to make certain entities more prone towards declaring war on others.
By the fact that we currently have Ethics for the entity, we can assume that attitudes are nearly entirely culturally and not genetically defined in DF.
Ethics effectively determine how 'wrong' something is to a certain race. They can cause wars when an entity finds something is particularly offensive about the ethics of another entity. However, this results in wars that are entirely based on cultural beliefs.
My suggestion is for the cultural expectations of the leaders, as well as the personality and situation of the leaders themselves, to come into play.
Format: [VALUE:X:Y]
Examples:
[VALUE:ALL:LEADER_DEPENDENT] Bases the entire value structure on the personality of the leader. If the leader is impersonating a god, they are restricted to values consistent with this impersonation.
[VALUE:CONQUEST:UNIMPORTANT] There is no onus on the leader to attempt to add to the territories acquired by the entity through conquest.
[VALUE:EXPANSION:IMPORTANT] The leader will direct the entity towards settling new, unpopulated lands. If no normally inhabitable lands are reachable, the leader may attempt to force settlement in less habitable terrain.
[VALUE:TERRITORIALISM:IMPORTANT] The leader is inclined towards protecting their realm with force. Territory overlap is not tolerated, and clear boundaries must be achieved.
[VALUE:WEALTH:PARAMOUNT] The leader is driven towards the accumulation of wealth. This defaults to the exploitation of the environment. If Expansion is important, it will drive the exploitation of new areas. If Conquest is enabled, it will drive the sacking of conquered locations of all their goods and returns the majority of those goods to the conquerer's homelands. If Slavery is tolerated, slaves will be put hard to work in driving the economy.
[VALUE:RELIGION:IMPORTANT] The leader will be inclined to listen to and obey the instructions of the religions with most sway in the entity. This would necessarily require SPHERES to have some kind of impact on entity behaviour.