Overall a slider for death rates may be best for this. I see that other people want to wipe out AI lords and clans constantly, vs my position where I want battles to be dangerous but have clans stay alive at least long enough for new generations to come to age (which I would also like to be faster - like, aging in general).
As a side point it'd be great if the game had a mechanic for mercenary clans to rise to noble clans if the number of clans falls low enough, as well as new mercenary clans coming onto the map at a similar rate... with an on/off option for these mechs.