I think it would be interested if you were to expand the ideologies into factions within my colony. There are already 3 ideologies represented in the game. It could be that each ideology comes with specific bonuses and negatives at the beginning and you can select whether you want to adhere to a specific ideology. As your society begins to grow, new colonists come in, each with their own random ideological convictions. If you selected a specific ideology at the beginning to be your political ideology that you want to run your colony under, this is really just a minor change, but as usual, when more and more people come in, difference in opinions and goals will naturally arise in every society. So once the total "ideological weight" of the other ideologies increases, your bonuses start to diminish and you get more and more events about disagreements and so on, ultimately ending up with sabotage and other incidents.
You can try to convince people of your own ideology with particular buildings to keep your bonuses, you could even only allow in new colonists that match your ideology, but every now and then even those who were formerly convinced of your ideology might change their mind, because they found an old book in the rubble and other convictions begin to grow, etc. At some point, the different ideologies would want some representation in politics in the form of a council (i.e., decisions, laws, focus on production of different things). This could lead to interesting synergies that are in some ways more beneficial than your starting bonusses. You can then try to run the colony as a more or less democratic council or as a dictatorship. The other societies on the map could also have specific ideologies and government types, so alliances would be more probable with other societies that match your conviction.
This sounds like a pretty different game, but I think you could keep it pretty nicely confined to an additional layer that gives your colony and its relation to other colonies some additional flavor and the actual effects on the gameplay would simply be a new system for bonuses and negative sideeffects, some additional buildings, some kind of "ideological unity" metric, slight differences in how the relation with other colonies is handled and lots of new events. For people who have the "New Alliance" DLC, you could then even justify the adversary by simply having him be a dictatorial leader of one of the other ideologies.
