One thing that would resolve all anyone's problems on this would to make Regal name changes available for independent lords (or Dukes + Kings + Emperors). So, you could be born named Eugene, but when you become King of England you will rename yourself William II, in honor of your grandfather William the Conquorer. Simple, and effective. It wouldnt force anything on anyone, since you could simply keep as a Regal name your birth name. That way, everyone's happy 