Hello Creative Assembly.
I appreciate all the work you're putting into the games you create and hope you consider my suggestion to bring back this old yet gold feature.
One of the things I enjoy in Total War games is 'Roleplaying' in a way, I know in ROME II I would unite all of Italy under the roman flag then act as a sort of 'Peace Keeper' for my 'Civilized Greek Factions' that I set up all around the world. I would focus on liberating these factions I deemed 'Civilized' in order to keep the Barbarians at bay. Instead of trying to conquer the world, I enjoyed creating stories and scenarios. One thing I wish I could do however was liberate Athens then grant them all of Greece to act as my 'Power' in the region, same with Egypt.
This feature has been long gone however, and I would appreciate it if you put such a feature into Warhammer :Total War. For example, I am playing as the Empire and witness my Bretonnian ally's removed from the map from Greenskins. How fun would it be to embark on a campaign to take the land back from the Greenskins, Liberate the Bretonnic Capital then gift all their lands back to form a mighty ally in the west?
Obviously gifting/selling/buying regions would require the following...
-Cannot gift/sell/buy your capital.
-Cannot gift/sell/buy settlements your factions cannot control (IE: Empire cannot take a hold)
Whether or not the offer is accepted could depend on variables such as...
-Importance of region
-Gold being offered/demanded
That is all I can ponder up for the moment, I hope you consider this and would be happy to see it implemented! (Maybe even implemented into Rome II and Attila)
I wish you the best in creating this game.