Possible Abuse Worry: Couldn't this system be very heavily abused by a ruler to prevent any regions from being in a duchy of his choice?
Ex: Say the Ruler dislikes Duke A, and Duke A has lords B, C, and D who are all very loyal to Duke A, more so than they are to the Ruler. The ruler decides to ruin Duke A's duchy and does so by appointing Lords B, C, and D as Dukes of their own right. This would destroy Duke A's duchy and reduce it to a single region (assuming Duke A is also a lord).
1. Would this prevent Lords B,C, and D from leaving their new duchies and once again joining Duke A's duchy since they now have the title of "Duke?"
2. If 1 is NOT true, then couldn't this lead to just a dumb see-saw where the lords choose to rejoin Duchy A, only to have the Ruler immeadiately kick them out of the duchy?
This seems like a horrible situation to be in, and I think has a lot of balance issues with regards to what Rulers will now be capable of. Perhaps a capability to choose: "refuse to become Duke" option could be available for lords to be secure in their current duchies without interference from the ruler? (I know there is a similar system currently in place, but I didn't know if this would have some problems since the meaning of duke is changing completely)