It might be an idea to reset some of the succession laws, when or where native dynasties were replaced by foreigners; or when (gradually) features from other cultures where adopted.
In case of the former, in the British Isles, that would mostly be Normans (and their successors); in case of the latter AFAIK (might be wrong) Scotland (at least their monarch and (part of the) nobility) did adopt Norman or even continental feudal ideas, at least from the reign of David I of Scotland (onwards).
An interesting idea, though I'm not sure how you would reset laws, except by banning certain laws for certain cultures, e.g. banning tanistry for the Normans