its pretty routine for a king to execute pretenders to the throne, traitors, rebels etc. Remember in those days being executed wasn't shocking. it would be done in public and people would bring the family out to watch it. Captured nobles might not be executed without a good reason. it would depend on the kind of war. I definitely think the execution penalty is too high across the board. Ideally there would be a system of checks where you can have justification for execution, and there should be positives to being ruthless too, people should be less inclined to fight you if evenly matched, because they are more likely to die. These things complicate the game though, and if the groundwork isn't already there, I doubt they have any intentions of making a more complicated nuanced system.
Right now just for playability in short term, either execution penalties need to be massivley reduced, or prisoner escape needs to be massively reduced.
