Increased Diplomatic Options for War

[Mobius34]

The general purpose of this is to add options for engaging in war beyond having a bigger army than the enemy. For a game about politics and personal relationships there is very little to no backdoor dealing and scheming during war, everyone just picks sides and sticks to them to victory or defeat with no betrayal or major drama happening.
(All numbers are speculative and meant for example, not necessarily actual balance)

Buyouts:
Spend money to persuade an enemy ally to leave the war.
Buyout cost would scale with the power of the combatant (for example an empire bringing 15-20K would cost 600-700 gold while a duke bringing 4K would cost 250-300 gold)

Circumstances can change to affect these prices:
Alliance broken, whether by a ruler dying and a new ruler not having the marriage to keep it or by assassinating the betrothed/married connection, the enemy is now less obligated to the war and is more willing to leave it.
Back to the empire example, that 600-700 buyout is now 200-250 without the alliance binding them.

Traits can result in prices changing as well, with the traits Honest, Just, and Temperate making buyouts harder, and the traits deceitful, arbitrary, and greedy making buyouts easier (10% increase/decrease for each trait)
These traits would also increase/decrease likelihood of AI accepting, thus looking at your potential allies personality traits is important in determining whether they'll screw you or not, making you avoid (or at least be cautious when allying) characters with bad traits.

Sabotage Relationship:
Hostile Scheme where the player can select a target's alliance partners to sabotage ending the alliance and causing the rulers of the 2 former allies to become rivals.
If scheme is successful during a war then the allied party will leave.
Small (15% with maybe an intrigue perk increasing it) chance of a critical success where the former ally will switch sides.

 

[Zeeg]

These are excellent suggestions! It can add so much to gameplay.

 

[Leonello d'Este]

Great suggestions. Diplomacy is one aspect of the game that badly needs to be revised.

 

[fodazd]

A agree that more dynamic diplomacy during warfare would improve the game a lot. Additional ideas:
-> If your opponent is in debt, you could try to convice some of their troops to desert.
-> The "swear secret fealty" mechanic from the recent Stellaris dev diary would fit perfectly into CK3.
-> Commanders and Knights who really hate their liege could be persuaded to disappear right before a crucial battle.

 

[Mobius34]

A agree that more dynamic diplomacy during warfare would improve the game a lot. Additional ideas:
-> If your opponent is in debt, you could try to convice some of their troops to desert.
-> The "swear secret fealty" mechanic from the recent Stellaris dev diary would fit perfectly into CK3.
-> Commanders and Knights who really hate their liege could be persuaded to disappear right before a crucial battle.

I didn't actual think of using diplomacy to attack the opponent directly, mostly focused on knocking out enemy allies.
Although yeah, these suggestion would be good for a diplomacy centric way to wage a war by convincing enemy to do things

Each of these goes along with the lifestyle theme:
Martial: The usual war, smash armies together and win
Stewardship: Buyouts
Intrigue: Sabotage Relationships (and the whole abduction thing that's already in)
Diplomacy: Convincing enemy subordinates to do things like desert, abandon liege and such

All that's really missing is a learning themed way to wage war, and I'm drawing blanks.
Maybe high learning can buff your war effort, like a 'streamline supply lines' decision that reduces your armies supply consumption (easier to implement than increasing supply across the map) as well as an inverse like 'sabotage enemy supply lines' which does the opposite for the enemy hopefully causing starvation, although that goes more for intrigue than learning.

 

[Blk82]

Buyouts would be too strong, as the the AI is bad at money management, and so would be OP for the player. You can't even separate peace in CK3, nor can you cancel alliances.

 

[Mobius34]

Buyouts would be too strong, as the the AI is bad at money management, and so would be OP for the player. You can't even separate peace in CK3, nor can you cancel alliances.

On the buyouts aspect, going into debt would be an option although it should be locked behind 50% of cost, so it the buyout cost, for example, 550 gold the AI would only need 225 gold to initiate the buyout (or consider buyout as an option).

Also the point of this is to add the ability to cancel alliances and knock opponents out of a war. With CK3 having such an emphasis on the interactions between characters it's a little silly that all of that goes out the window with war when people would be doing as much if not more scheming in order to get an advantage in war.