Multiple copies of Armageddon and Doomsday.

[Seravy]

While my intended solution to the problem these create is pretty much the "don't let that many wizards survive until the endgame", multiple copies of these spells might still use some fine-tuning on their unrest effect.

Currently you get +2 unrest for each Doomsday beyond the first and +1 for each extra Armageddon.

Maybe changing that to add +1 for any duplicate of either spell, and cap the total at 3 would be better?
With that, the worst case scenario is 10 additional unrest (5+2+3) instead of what's currently pretty much unlimited.
However that also makes the strategy of trading these spells away to escalate the effects ineffective.

Either way the effect is already moddable in the unrest script file and this should came up rarely, but we might want to adjust the default, let me know what you think.

[Dragonfabri]

Maybe the best solution is to split the themes: Doomsday becomes purely based on unrest, while Armageddon loses the unrest component and gets some compensation.

For example, Doomsday could cause 7 unrest, and each copy of it adds 1, no cap.

Armageddon could maybe convert ocean tiles into volcanoes too and increase the number of tiles affected.
This could improve the baseline possibilities of Raise Volcano for both terraforming, power generation, and even new land for future colonization. (but not colonizable until the ARMAGEDDON stops, it's already the effect of the spell to destroy settlements).
Not to mention, it is very accurate to nature since most volcanoes are actually underwater, AND new land emerged this way ages ago!

[Suppanut]

I prefer no cap in unrest and let's uncontrolled late game into extreme endurance test. Whole global unrest thing hurt player more than ai on higher difficulty anyway.

If there would be any solution then I would suggest for more modifier on what kind of situation that ai would want to do disjunction, such as
1) if ai not have specific realm spell books enough to have key spell to counter it
2) different global curse should have different level of diplomatic penalty depend on ai type and realm such as perfectionist ai would absolutely disgust on meteor storm etc.
3) AI should also much less likely to make peace with wizard that maintain or already have global enchantment that might be highly threaten to their playstyle
4) if they unwilling to disjunct such spell then they should be more willingly to team up and banish or defeat that wizard to eradicate such deathly threat (such as coalition against Napoleon).

Also, if you really don't like ai wizard throwing disjunction around so much then I have suggestions.
1) disjunction should cause aether fatique and prevent target wizard from cast the same global enchantment that was disjuncted for a period of time depend on amount of mana spend on disjunct such global enchantment
2) each time wizard get banished, there should be 20% chance for each global enchantments under wizard control to lose due to disruption of his/her control due to banishment shock. This should serve as alternative to casting disjunction (militarist solution)

[Slingers]

Maybe changing that to add +1 for any duplicate of either spell, and cap the total ...

Sounds almost ok, I think. Actually, one Doomsday/Armageddon should be enough for one world. In any case, it shouldn't worry the already panicked people even more if the world threatens to end more than once. Perhaps - instead of a hard cap -the probabilities of using these spells and their disjunction could be made dependent on the personalities of the wizards.