Oh yeah, I remember you talking about that a few months ago. Did that upset you?
I can see your point and I think you're right, but, do you mind clarifying what you mean by "the diplomacy element of the game" - while it make sense that individual cities' separatism on a huge map is less of an issue, how does the scale of the map or number of civs significantly affect balance with respect to certain civs conquering everything and running away with the game? I guess technically you can have more people to call in with defensive wars, but that goes for the aggressor too, and if someone is already powerful, they're going to be feared and respected by people they solicit to help them in their own war, so I don't really see how that prevents snowballing.
Upset me? No. I was just concerned that you might have been playing on the fringe (smaller map with fewer civs) and yet insisting on changes that affected all styles of play.
Regarding my comment "the diplomacy element of the game," I was referring to how a huge map with many civs will likely mean that many civs will lack enough resources to lead in early game development (in my game I lacked enough limestone to get masonry materials, and it slowed down building and road development). I was able to find several prime timber tiles to trade for some limestone. Larger civs (as a result of fewer overall civs competing for territory) means that they will have much more resources at their disposal, likely everything they will need when they need it.
This is where the comment about "certain civs conquering everything and running away with the game" comes in. I'm saying that it slows down the likelihood of civs doing this. All civs will be resource-constrained in a game with a very large map and a lot of civs, to the point that creating SoDs becomes prohibitive. What happened in my game is that by the time the leaders enter the industrial age, there are still a lot of civs that were unable to compete and are still building old wood siege weapons. These are the civs that will ask to become your vassal. This is where diplomacy really comes into play.
Once the weaker civs look for masters, you have to pay attention to which civs like or dislike the civs that want to become your vassal. Accepting a civ as a vassal may give you open borders to a section of the map that was closed off to you before, but you now will have civs who say you traded with their worst enemy. You may get civs who decline to become vassals because they are afraid of your enemies or that their rivals are in your empire. When you start attacking other civs, some of your vassals may cancel the vassal deal because you attacked their friend, and then a few turns later they become a vassal to another civ.
Eventually, I find that the civs that vassal to me will start trading amongst themselves. If I find a civ that is trading with a rival of mine, I will ask that civ to stop trading with them. Eventually, a trading bloc will form amongst my vassals to the point where it becomes economically infeasible for them to leave.
I suppose this comes down to how you choose to play the game. If you want a wargame where domination is the goal, then none of this matters. If you're playing for a cultural or diplomatic win, then this becomes important. If you're playing the space race and need to lead in tech, then negotiating some form of "coopertition" with your main rivals (where you are #1 or #2 and have open borders with tech transfer) may keep the top civs from direct conflict. I found in my games that smaller regional skirmish wars flared up every now and then between the #4-6 civs and their vassals. I usually ignore these as being inconsequential to me.
I'm almost finished with my v3.5 game and am looking forward to starting a new game with the newest release. Until then, I can't really comment on how the war weariness/separation adjustments affected the huge map/many civs game. I did see some civs break up in the medieval period because they couldn't afford their expansion (I assume), but none of the leaders in the late game are suffering this. It might be because these civs are not diverting their economies to military unit-building (SoDs) because they are not driven by conquest. It might be that civs are not separating because of war weariness because there are fewer wars.
My one exception in my game was with the Ashoka leader. He and I were battling for #1 and #2 and we each had about six vassals. Eventually, Ashoka sneak attacked me. I was able to sink his invading transports, and then diverted all of my research to construction, built up my own navy, destroyed his defensive forces, and blockaded his coastal cities. Then I had the time to build up my own invading army and destroyed those same coastal cities, driving Ashoka back. He dropped from #1-2 to #5-6, and he was eventually attacked by some of the #3-4 civs while restarted my research, but was upgrading my military units one by one each turn. About 60 turns later, I attacked Ashoka again because he kept starting wars with his neighbors no matter how small he became. I eventually declared war on him so my vassal closest to him would occupy his capital and eliminate him from the game.
But other than that war, it's been a mostly peaceful game. I attribute this to the dynamics of a huge map with 40 civs. I'll play the new version using the same setup and see how it compares. Then I might try a giant map with 40 civs to see if having more space will give the civs access to more resources, and if having more resources tilts the AI to be more warlike.
Of course, one has to have a computer that can handle this. I'm playing on a Dell Alienware m17 R4 with 16Gb of ram and a dedicated GPU NVidia RTX 3070. I still need to run Process Lasso w/Watchdog to keep the MAF errors from happening.
I hope that you get to try a large map/civs game to compare to your own experiences, too.