Certainly possible, but I'm rather wary of the settlement ancillary system for several reasons:

- You can only give, not remove settlement/region ancillaries via code, so if say the Count of Dijon still lives and hides in Baghdad with the Counts of all French settlements, then good luck getting those ancillaries when you take all those towns. If you still give the ancillary, then you end up with a lot of Counts of Settlement X. If you don't, then you can't get it as long as those people are still alive somewhere.

- What system should the ancillaries follow? Say you take Constantinople as the Turks. Do you want to be King of Byzantium or Amir of Istanbul? If you follow a standardized system applicable to all factions, then you are bound to run into inconsistencies and odd situations like the above. Every faction will call the reigning Lord of a region differently. A HRE leader might be a Margrave or Elector, an English one a Count or Duke, a Muslim one an Amir, a Mongol one a Khan etc. Unless you call a settlement title differently for each faction or group of factions, which is a huge amount of work (i.e. faction number times region number + code to crosscheck), would it really enhance anything?


From my perspective, its possible to address the first point by using traits rather than ancillaries, but this way they won't be transferable, which kind of defeats the purpose, but at least the person who takes the place also will be the only one with the title, and you can even force characters to stay within that region's borders to hold on to the title. It would be a lot of coding work though, and less flexible than the ancillary system in some ways, more flexible in other ways.

But of course I would invite you to discuss this here with me further to reach a conclusion that is amicable to everyone.