Now that we can do fun and amazing things with prisoners, I find myself wishing for the things we SHOULD be able to do:
Educate children prisoners (Drakul's sons come to mind). "Oh, my rebellious Bohemian Duke, I have your kids and they will be raised as proper German Catholics!"
Arrange marriages (looking at you, Maid Marian and Sansa Stark).
Perhaps take it a step further and allow *all* diplomatic actions on a prisoner with "offer release" as an option (much like "use favor") so you can tell the AI especially "I will release you if you marry your heir to my son."
Educate children prisoners (Drakul's sons come to mind). "Oh, my rebellious Bohemian Duke, I have your kids and they will be raised as proper German Catholics!"
Arrange marriages (looking at you, Maid Marian and Sansa Stark).
Perhaps take it a step further and allow *all* diplomatic actions on a prisoner with "offer release" as an option (much like "use favor") so you can tell the AI especially "I will release you if you marry your heir to my son."