TL;DR:

A system of Ethical pressure across borders, increasing the ethics divergence of distant planets towards that of neighbouring empires. This would scale with open borders, embassy placement, proximity and planet density and research/trade agreements, alongside specific cultural buildings that could be built by players.



More focus on the faction system, allowing players to apply pressure to their neighbours and increase internal strife. Focused more heavily on outlying planets, increasing "frontier" divergence and causing pops to flip towards your ethos.

Empires can now engage in "cold wars" during peacetime, pressuring nearby planets towards their ethos and eventually towards their empire ownership. Factions would seek to flip to nearby empires that have their new ethics, giving a relatively peaceful way to acquire new planets with enough cultural pressure.

Militaristic Empires can utilise this to pave the way for conquest, changing pops to their ethics in advance and reducing the time it takes newly conquered planets to fall in line.



Mid- to Late-game galaxy becomes less static, with planets and sectors changing allegiance to new empires as the game goes on, while Empires have to look to their own ethical divergence and culture to maintain large sprawling expansion.

Core Systems

Cold War and Border Frictions





Paving the way for Warfare, Factions and Liberation





Balance changes to Ethics

Xenophobe: Currently, somewhat inferior to Collectivist, particularly given the negative diplomatic modifier it has. I’d add a -25%/-50% (fanatic) reduction in incoming ethical pressure from other Empires for Xenophobes, to simulate their distrust of outside influence and ideas. Xenophobic Empires would thus be much more resistance to this ethical pressure than other empires.

Currently, somewhat inferior to Collectivist, particularly given the negative diplomatic modifier it has. I’d add a -25%/-50% (fanatic) reduction in incoming ethical pressure from other Empires for Xenophobes, to simulate their distrust of outside influence and ideas. Xenophobic Empires would thus be much more resistance to this ethical pressure than other empires. Individualist: I’d add an additional +10%/+15% to outgoing Ethical pressure from Individualist Empires. Coupled with increased Ethics Divergence already present, Individualists would be both more susceptible to this system and more capable of putting out their own pressure – representing a free exchange of ideas within the Ethos.

I’d add an additional +10%/+15% to outgoing Ethical pressure from Individualist Empires. Coupled with increased Ethics Divergence already present, Individualists would be both more susceptible to this system and more capable of putting out their own pressure – representing a free exchange of ideas within the Ethos. Pacifist: Not an actual change to the Ethos, but more of a tacit one. The extra one/two Embassies available to Pacifists would allow them to seed their Ethics into more Empires than others, spreading their propaganda more actively than others and possibly obtaining new worlds without conquest by force.



Conclusion

So, to help spice up the mid-game and provide some variety to the military focus of Stellaris, I think the game could benefit greatly from a system of “cultural pressure”; this would be heavily tied to the existing Ethical Divergence system. The pressure would press across empire borders, increasing ethics divergence in nearby planets towards those ethics believed in by the other empire. This would being a new mid-game system for players to focus upon and increases the need to manage your Empire internally, particularly for expansionists. To help save everyone some time, I’ve put a TL;DR summary right here at the start so you can decide if you’re interested in the longer explanation below.The pressure – represented as additional ethical divergence on a planet – would stack with the distance to the borders of each empire, the volume of inhabited worlds nearby and the amount of pops with that ethos on the worlds. In general terms, proximity and population density would push ethics onto other worlds. As such, frontier planets and sectors far away from the empire’s core worlds would be much more susceptible to pressure from other empires.This pressure can be influenced by players to their benefit. Several cultural buildings would increase the pressure after being built in border planets, such as trade hubs or concert halls. Similarly, larger unique buildings could be built to give an empire-wide boosts: cultural exchange building or a large Imperial Museum. Pressure would also be boosted by embassy placement (increased pressure on empires that host your embassy through propaganda), research and trade deals (exchange of ideas with knowledge/goods) and open borders. Closing your borders would severely limit this pressure.During peacetime, as empires expand into the mid-game and borders begin to press on each other, the Ethos of each empire will begin to erode and convert pops of surrounding empires to their ethics. This is a two way system – pops of both empires can feel this pressure, though if one empire is putting out a lot more pressure and converting more pops, incoming pressure to that empire will begin to reduce.This is designed to represent that nature of borders, far away from the imperial “core”, whose people will interact much more frequently with the population of other empires through trade, discourse and exposure. It also gives the player a peacetime system to focus upon that will directly affect and weaken their neighbours, sowing discord and discontent into nearby star systems. To visualise this, a good example would be Firefly – the internal core worlds adhere fairly rigidly to the tenants of the Alliance, while the outer planets are more lawless and individualistic, far away from the rigidly enforced laws of the core.Initially, at a basic level, this system of exerted pressure will increase the internal strife of all Empires. Players will have to focus more to manage this pressure and their empire internally, bringing more focus to the faction system that I feel is currently a little underutilised. However, this is simply the basics. I think players should be able to harness this pressure to fight cold wars and increase the discord of their neighbour, utilising superior cultural output to increase the attraction of their own empire to others.With enough pressure and near total conversion of a planet to the ethics of one empire, planets of another empire might choose to flip entirely to the ownership of the empire whose ethics they believe in. Similarly, a new faction might form that wants to secede from their overlord and become a vassal under the other empire, whose pressure is causing the discord – this faction might contact the player, requesting military support in their attempt to leave their empire.The end result is that, with careful management of the pressure your empire exerts on others around it, you can conquer worlds without actual war entirely or minimise the outrage/integration time after conquest by pre-seeding your ethics into populations you intend to capture. This also causes the late game galactic map to be much less static, with more fluid borders and planet ownership particularly for large expansionist Empires with more distance to their capital.To help integrate this system into the game and to give a bit of a buff to a couple of ethics I think are a little underpowered right now, I’d also propose these changes to the general ethics balance of the game:I believe this system would help alleviate a couple of issues with an otherwise excellent game – namely, the slow-paced mid-game and the heavy focus upon military might above all else when it comes to claiming territory and growing your Empire. I think it would also help bring the internal strife that would face a Galactic Empire to the fore, particularly in a game which looks to make each Empire unique in their ideologies and beliefs – I’d love to see these differences become a larger element of the game. Any thoughts? Is this something you might want to see in Stellaris?