Yes that would be best, if you could make a script that says if faction has < 1 settlements and < 1 military units. Cause I agree a faction shouldn't be destroyed if they have a army left, but when they dont, well...............
In my campaign the Zora Domain are utterly defeated, no units no settlements, yet at the end of my turn I have to wait for their 3 dam diplomats to try to talk to me, which they never do they just do that stupid motion at my city and never open diplomecy. So annoying, and Laybrnna doesnt have assassins to get rid of them.