True, virtually all Empires/Kingdoms needed to be adept at war but there was also measure to it. Empires had significant limits on how far and how quickly they could expand. Attrition was generally so extreme that the majority of wars have ended with nothing but minor transfers of land and gold. In Civ you generally just wipe out a rival all but completely, the idea of trading back the cities you took is OMG incomprehensible. The idea of stretching your borders too thin to actively defend is laughable. War in the game is simply too powerful, and would be made better (IMHO) if there were more limitations on it.
A few things I'd like to see...
Significantly slower regeneration the further from your capital, with adjustments made for being closer to cities that have been in your Empire for longer (and further bonuses for increased sizes, to encourage spending time growing cities).
Localised happiness issues in conquered territories. When you initially conquer an area it will take time to settle down, and rebellions will kick up from time to time. If you don't spend time spreading some culture (or suppressing using military - which should have different cost/benefits) then this will continue to be an issue. Again you can increase this with distance from your capital.
Being in territory that has no direct access to your own territory either through unclaimed, or friendly civs causes attrition each turn. You could even ramp it up by having only a limited distance over neutral territories allowed. Hell I'd even like to see supply trains, which could act like traders currently do, but link them to unit or Great General. Then anything within X distance of that unit doesn't take attrition. But the further you are from your own territory the more supply trains you need, and if they get raided you lose the train and take damage to your army.
I totally disagree, this will remove the fun in the war game, and will make it a big chore.
The game already has several systems to prevent excessive expansion: Loyality, grievances and war weariness. Maybe they could be reffined a little bit, but to add additional mechanisms to prevent expansion is kind of ludicrous in my opinion.
Besides, in general war and expanssion in Civ VI is far less prominent than in history, in the historical equivalent of one single game we had incredible expansionist empires 'China, Rome, Greece, Egipt, Mongols, Otomans, France, England, Spain ...' several instances of Civilizations entirely wiped out and entire continents being colonized.
The main difference is that most of these empires had fallen or dissapeared due to the encouter with a more powerful empire, internal wars, religious pressure, or simply not surviving to the death of the people who created them.
You will not see as many expansion or fall of empires in Civ as in history.To make the game more realist, the path would be to make war more relevant, not less. And the AI more expansionist, not less.
Anyway, as a game, real history should be only a general reference for game mechanics, is not supposed to be extremely realist. It is supposed to be fun.
I think that taking what already is the most realist part of the game and removing the fun by making the player pushed back by 4 or 5 different game mechanics is a terrible suggestion.
Also that would probably make the AI uncapable of expanding at all.
The solution to limit expansion is to make other enemy civilizations more expansionist, and more capable to fighting back the expansion of the player.
Taking back the agency of the player with game mechanics and timers is very frustrating. On the other hand, enemies that fight back and pose a challenge is what most players consider fun, I think. And that is the main complain of players with the current state of the game.
So in this case, both historically and gamewise, war and expansion should be more relevant in Civilization, not less.
