i don't know if this is already in the expansion (i'm poor so i don't have it yet), but what if you take a pawn noble prisoner? you would take a rep-hit obviously, but what if they came to get them back? imagine if you got raids specifically to liberate the pawn you took prisoner, imagine a 'sapper' style raid to break out your noble prisoner! the attackers would try to make for your prison cell to break in, and carry the pawn out (same as when raiders take downed pawns after a raid, but prisoner would not need to be downed to carry). when a pawn is carrying the prisoner and making for the edge of the map the others would adopt a 'protection' behavior similar to domesticated animals, staying near the pawn and protecting from harm. once the 'carrying' pawn is off the map that would be the end of it, but what if you beat back the 'prison-break sappers'??
imagine if after beating back 2-3 attempts a quest is sent offering a 'ransom' for the safe return of the prisoner. maybe offering loot, maybe offering a promotion (respect for formidable opponents - sort of "we need more like you, joins us"), or perhaps both. but it would be difficult to do, fighting imperial style troops - definitely not like your basic raiders.
i don't know if it is practical to implement, i just thought it would be an interesting idea...