I get that those are HOW you win, but I'm trying to find out WHY, to see if there's anything I can do to reduce the problem. For instance:
1. I've outright won the game via domination.
2. I've gotten to the point in the game where I know I'm going to win via domination and don't feel like I'm gaining anything by continueing to play.
3. I've outright lost via domination.
With domination wins, what is the tipping point? Is it that you get nukes, wipe out the enemy capitals on the first turn, and are then unstoppable (or get nuked unexpectedly and now can't recover)? Or are you rolling over the AIs with modern armor, mech infantry, and stealth bombers? Or is it still competitive up until you get Skimmers and Vertols?
If it's nuke-related, then my next version should really help. What I'm trying to do is this:
Manhattan Project adds 20% nuke interception, SDI adds 40%, and the Orbital Defense Pods add 4% each (you can build 10), which'd total 100%. (ODPs will also reduce the damage dealt by enemy orbital weapons by 5% when they target your cities or units, so having all 10 means an enemy Orbital Death Ray's base strength drops from 150 to 75.)
But, I'm trying to then modify the nuke interception chance based on the weapon type used; Atomic Bombs would be 150% of normal, Nuclear Missiles 100%, Planet Busters 50%. So even the Manhattan Project would give you a 30% chance to stop incoming atomic bombs, and adding the SDI would raise that to 90% for atomic bombs (60% for Nuclear Missiles), which should drastically slow down the early-Digital nuke spree. Even in the endgame, a Planet Buster would have a 33% chance of getting through, so these weapons would still be useful against other empires, and city-states have no nuke defenses at all.
(These numbers are subject to change. I might drop the Manhattan to 10% and raise SDI to 50%.)
I'm hoping that these will slow down the nukefest without eliminating the utility of nukes entirely. I'm also going to tweak the flavor values a bit, and make nuke units go obsolete a little faster than before to encourage the AI to build the more advanced (and more expensive) nukes instead of churning out atomic bombs.
If you're doing this with conventional units, then there are other things I can try. One possibility was to rebalance all of the strengths. For instance, the Modern Armor is 80 in the vanilla game, and I lowered it to 70. What if, instead, I changed it to 60 but with the Blitz promotion for free? (Still an upgrade of the 50-strength Tank, especially with the increased move rate, but not as severe of a jump in raw power.) And then I'd similarly lower the Gunship, Vertol, Skimmer, and Gravtank... if I can get the All-Terrain promotion working for the Vertol and Gravtank, they won't need the extra power anyway.
4. I've outright lost via UN Vote (almost exclusively this is the Siamese and Greeks who win this way).
Is this a win-on-first-vote thing where it hadn't occurred to you to bribe any city-states up to that point (meaning you now avoid losing this way easily), or do they ever win the UN through gradual accumulation of votes AFTER the UN is founded (where even though you might try to stop them, you just can't do it)?
One thing I'm considering there is boosting the diplomatic ratings of civs other than Siam and Greece. America, for instance, could be more willing to bribe city-states; not enough that they'd be able to overcome Greece or Siam in a diplomatic win, but enough that they'd pick up a few allies here and there and keep Greece from sweeping them all. France and England would seem like likely choices for this as well as the empires that went through major colonial phases. (I don't have any of the DLCs.)
its just that the crashes are occurring often enough (once every ten-ish turns?) that its not worth pressing on.
Once per ten turns is a lot better than it used to be, but it looks like the crash is inherent to the game, and occurs whenever an improvement/resource/whatever is deleted graphically. In the vanilla game this won't happen often, but in the future eras every tile will be improved and all non-water resources will require you to create a new improvement in place of an old one. I've definitely crashed the game using only pre-existing improvements, though, when I tried placing a mine on a uranium that had a trading post on top of it.
There's one little bit that I can try improving on this, still, involving art definitions, where I think it might be having a problem with some unset variables. So it might get better through my own efforts, but it's more likely that you'll have to wait to see what the next official patch does to the stability. (I know they're working on reducing crashes.)