Question: how well are the AIs handling Psi units in regards to the Breakout event? Are they able to contain the MWs and destroy the Spore Towers?
Major empires that haven't been in wars recently tend to do just fine. They go after the spore towers before they have a chance to spawn lots of units, and it works out well.
Major empires that have just been in a major war and have depleted their reserves will often have problems, at least until they churn out a few more units, and thankfully this is one area where the AI has overrides in place (making military units a higher priority if it feels it has too few). Of course, the system is geographically based, where smaller empires have a lower chance of a spawn, so this one's somewhat self-correcting anyway.
City-states are very hit-or-miss. Some build more than enough units to handle it, others get overrun. This was actually somewhat intentional; despite their secondhand units, city-states will continue to fall further behind the main empires in power in the future eras, especially once you hit the mid-Fusion. C-S's top out at Gravtanks and Needlejets (both weaker than the normal versions), while major civs continue on to Titans and Orbitals.
However, once the majors get orbitals, they'll take out towers regardless of where in the world they are, so it still works out pretty well. (AIs do know to attack barbarians wherever they can, and now that I've got the PlanetPearls award going, it's not unbalanced to do so.)
Also, how well is this working on Archapeligo style maps? If you haven't playtested that mapscript against this, why I can do that this evening if you like.
I've never tested a full game of it, but I did test a bit. Frankly, it's a whole different experience.
The spore towers that spawn in water within 5 hexes of land will move to the nearest shore. On normal maps this means that occasionally you'll get a tower spawn on a tiny island in the middle of nowhere; when that happens it almost never dies before spawning units, and you'll see two things: a good number of Isles of the Deep spawning, and the island will get stacked with mindworms. (I'm honestly not sure about that last part; I kind of like the idea of having to blow through worms before getting to the real threat, but I don't know how well the AI would sustain that sort of clearing operation.)
On an Archipelago map, more towers will be like this; you'll be much more likely to see them survive, and when you do get to them they'll be harder to clear out, but they'll be significantly less of a threat. Sure, the isles will be a pain, but a few stealth ships and needlejets can manage that just fine. And not having mindworms swarming all over you would be pretty nice.
My concern would be what happens in the late Fusion Era, when towers start spawning Nessus Worms (which are supposed to move across both water and land), since those wouldn't be pinned on the tiny islands and would seriously threaten your core cities. But the Godzilla jokes would be too good to pass up, so I'm okay with that.
The more I see of situations like this, the less I like the combination of impassable terrain, cultural borders, and 1UPT: an AI simply isn't programmed to take situations like this into account, and will blindly follow its programming to its death.
This is actually part of the reason why every unit in my mod has some sort of improved movement ability, most often the "all terrain 1 MP" promotion and higher movement counts, and many can move through impassable terrains (like those mountains). Combined, these keep 1UPT from crippling the AI so much; it no longer has to spend multiple turns moving through killzones to get to the targets.
This is why I've been spending most of my time trying to figure out a way to get the All-Terrain promotion to work. Vertols, Gravtanks, Nessi, and the Gravship all have it, and those first two should be the backbone of Fusion Era wars. The idea is that with this promotion your unit should be able to move full-speed across water, with full offensive and defensive ability, and move onto shore in force. Between those, the improved paradrop ability of the powersuit units, the free paradrop from the Aerospace Complex, and the orbital weapons, I figure that most future-era wars would not be crippled by that sort of terrain issue.
If it works out, I might even retrofit some of this to the earlier eras. For instance, I've added (in my upcoming version) an "Airlift" promotion to the Aerospace Complex; units that start the turn in the city get one free range-12 paradrop. It's not as flexible as what the powersuits get, but it should help a bit with getting units across small bodies of water or over mountains, since the AI tends to keep its units in cities anyway.
So if that works out, I might add an Airport building back at Radar that gives a range-6 version. Obviously more limited, but it still might be enough to get the AI to bypass those mountains you were using.
I'm also seeing another tactic (exploit?) where I won't accept a peace treaty from an AI.
That's fine if you just want the little bit of XP, but remember the negatives, like the stacking SDI bit we talked about before. And there's always the chance he'll get a unit of uranium and nuke one of your cities, which immediately would cost you far more than the little bit of XP gain.
Frankly, I wish there was some sort of War Weariness mechanism again, or at least a more granular warmonger diplomacy hit (where the longer you stretch out one of those lopsided wars, the more everyone else hates you). I'd be hesitant to add one of my own, because the usual "AI would have no clue" disclaimers still apply, although the fact that the AI doesn't stretch out wars like this anyway works in its favor there; adding a penalty to empires at war wouldn't be much of a downside to the AI, as long as the penalty grows slowly enough that they wouldn't normally kick in.
I've already got negative-happiness buildings, although they're limited to even numbers most of the time. So all I'd need to do is, for every turn you're at war, there's a 10% chance per enemy major civ, that a, invisible, stackable -2 Happiness building appears in your capital. When the war ends, they'd all go away. I could even modify this by having successful kills have a chance of removing a building for the winner and adding another one for the loser, but I think that'd penalize the AI too much. (Downside: if someone captured your capital, all of the negative buildings would have to go away and wouldn't transfer to the new one. I suppose that could be viewed as compensation for the civ that just got gutted...)
Again, the AI wouldn't understand that the war was causing that unhappiness, so I wouldn't want to push it too far, but AIs already tend to make peace with each other fairly quickly.
I could even take this further and when the negative happiness from war starts getting too large,
even if the net happiness of your empire is still positive, you start getting other penalties. Negative promotions for your units, anarchy in your cities, that sort of thing. Having your production city suddenly go into one turn of Resistance would obviously be a major downside...