George, as Ken says this has been covered many times in many times in many different discussions. We can definitely re-work the wording if we can find something that better expresses the idea.
Despite the genealogical convention of always using the birth name, for titled nobles the birth name is arguably a very insignificant piece of information. People want to see Henry VIII, King of England, not Henry of England.
We don't have a prefix field on Geni, so the only way to capture the information is to use the display name.
You and I agree that the number is not part of the birth name. Henry VIII was not born Henry VIII. But, we're in the minority (so far). Even many curators think it is better to put the number in the name.
Also, there are many cultural differences. English nobles weren't usually born with titles, but German nobles were. And, when Germany abolished titles, those titles became the surname. So, we always have to struggle with different rules for different countries and different time periods.