Are there any xml modding changes we can make to make 'run-away' factions (be them controlled by either the AI or the player) less certain to dominate and win the game without being challenged after they conquer a certain percentage of the galaxy?



In my games, one faction (often the Hisho; though not always) successfully invades and conquers all or nearly all of a neighboring enemies systems. Suddenly they have nearly half the 'pie' (shown each time you quit the game) on many of the game's most important categories (number of systems, population, fids, military power and size). At this fairly early point in the game, the only way for them not to win is for everyone to gang up against them (either war against them or at least don't trade with them) or for their conquering expansion to create great internal problems with these newly conquered systems. Because of the difficulty level I play at, I'm usually not the one to achieve this early mass conquest because it takes a while for me to overcome my early disadvantages.



Civ 5 addresses this problem with harsh, war-mongering diplomatic penalties. This is not a bad idea at all. I suppose it's already in ES to a certain extend with expansion diplomatic modifiers, but I don't think it's enough. Those don't seem to distinguish between peaceful colonial expansion and aggressive conquest expansion anyway.



An additional solution is to make the early-game conquering faction have great difficulty maintaining their newly-conquered systems. This could include a very slow (slower than it is currently) ownership-rate, 'rate-of-return' on newly conquered systems. So, for a while, the only advantage gained from conquering these new systems is that they are denied to a neighboring faction. Eventually they will contribute to the conqueror's economy; but for a long time they lay in ruins or, even if they aren't ruined, their is little-to-no co-operation from the race of the conquered, subjugated system.



Most importantly, this should be worse on each system based on the number of total systems taken during a single war. For example: The Hisho declare an early war against the Sophons, who are ill-prepared. The Hisho are in position (militarily) to take every single last one of the Sophon's systems. Let's say the Sophons have five systems. If the Hisho take one by force, then another as a result of a cease-fire to end the war, the problems the Hisho have with these two systems should be significantly less on each system than they would be on each system if the Hisho had conquered all five Sophon systems. The key here is that it's easier (for the conquering Hisho) to deal with the unrest, destruction, cultural differences, assimilation, etc... simultaneously on two systems than simultaneously on five. Of course, new occupation governors and special/secret police come in and slowly bring order and change, but this is abstracted in the game. Simply put: these occupational forces have limited manpower and resources. Therefore, assimilating/re-building two new systems is much easier and faster than doing so for five systems. Maybe the 'ownership' rate increase for newly conquered systems should decrease based on the number of systems currently not at 100% ownership. So if you had two newly-conquered systems, each would increase in ownership by half the rate than if you had just one newly-conquered system. Basically it would abstractly represent having to spread your occupation/assimilation forces to two different worlds instead of one; making each possess half as many personnel. I really hope this can be modded in somehow!



This change would encourage conquerors to limit their war goals and not just conquer every last enemy system when they realize they have the military to do so. This would slow run-aways and also give some hope for the defeated faction (who would have been completely eliminated with the old rules) to make a come-back; probably with the help of other factions that don't want to see the conquering faction grow any stronger.



To use a Star Trek example: The Federation and the Romulans have a poor relationship, with little trust on either side. but if the Cardassians completely conquered every Klingon system, The Federation and Romulans would have to put their differences aside and unite against Cardassia. If not, game over: Cardassian victory is a for-gone conclusion. The Federation and The Romulans wouldn't have to both attack the Cardassians right away, but they would have to not fight each other and stop trading with the Cardassians. Meanwhile, as the Cardassians have to deal with the enormous problem of maintaining order and eventually turning profit off of these worlds with extremely hostile populations (and doing so on all of these newly, conquered systems simultaneously, with thinly stretched resources)... the Federation and the Romulans are spending their resources developing infrastructure, researching new tech and building advanced ships. In this scenario, maybe The Cardassians would have been better off conquering a smaller percentage of Klingon systems and then making peace. Then their task of governing the newly acquired, previously Klingon systems would be faster and easier. Then later, after these new systems had been stabilized, they could declare war on the Klingons again and take some more.



and for sake of gameplay, this could do wonders for balance and preventing early run-aways that are never caught. Maybe the happiness state of 'rebellion' could also be made more harsh, because if this new slower ownership rate based on the number of newly conquered systems was implemented, factions that take many systems at once would have more systems in rebellion for longer periods of time.



Is there anyway that any of the things I mention here could be modded in? even in the most abstract way? Thanks in advance.

Civ V's "warmonger penalty" system is completely awful. You are correct that it helps prevent runaways but it has way too many negative consequences, as anybody having played it can attest to - such as the absurdity of being 'hated' by the entire world several hundred (or even thousand) years after conquering some player. You already pointed out yourself a model that would work well: Players ganging up on the leading player. Other empires should prefer not to trade with the leading empire and have a generally more negative attitude towards it.



Sadly, such a model is present in very few games and I've yet to see one that does it well. IIRC, Distant Worlds does use this system.



I don't know about modding it in. To me, it is obvious that any 4X game should have a such system and it is baffling that virtually no developers create it. Thus, we have 4X games with runaways. I wish you best of luck if you do try to create a mod for it.

What about a malus in diplomacy if your total of troops > to the mean total of troops ? (and vice-versa)



Say I'm in the more or less usual french mood "don't like USA cause they are always at war". Or "don't care Thailand because they don't threat anyone", would that affect my ability to do buisness with them, and / or be friendly to them as a president ?



Maybe yes, but not that much.