Currently, raiders can raid with impunity because at worst they lose some troops, then flee and laugh at the victims. I think non raiders should be given a chance to demand reparations or vengeance, with a diplomatic action or a CB like AGOT mod's Bloody Vengeance CB. If possible, it might even force a war with raider hosts, letting the victim destroy them because they don't run away for years to reinforce after just one lost battle. This should specifically be available for the AI to make them less defenseless against raiders.