Personally, I'd like to see something like this added for the simple reason is that our former monarchs in Westmoor are called Princes or Princesses as a nod to their service, no matter what other title they have. Yeah, they have the "Royal" flag (unless they left and came back, as was the case with Evangeline Uceek once before), but that doesn't have enough of a nod to their service, IMO.
Ah, this would be a very good use of the idea, I think.
Not just for retired monarchs, either. The ruling Monarch could use it to denote a "chosen" successor. Whether people choose to recognize that blessing when the time comes, however, it up to them.