I don't think the player should actually become nobility, rather work for a noble or someone who has aspirations to become nobility. For one if the player was actually Nobility then from a lore standpoint it would be hard to say why there was an Argonian ruler in a Skyrim hold, also from a gameplay standpoint it would be to constricting if Beth created a believable system for Nobility. I'd prefer a cross of Daggerfall's Nobility system with Morrowind's Great House system, while restricting the player from gaining too high of a position.
It could be intergrated i the Radiant Story: The Bretons, Nords, Imperials and Dunmer(yes dunmer, a dunmer city is more or less confirmed) could become "real" nobles while the other races get more restrictions and would have to work more behind the scenes.
I would love a proper title like Duke(my preference) but as I mentioned it would probably be hard to add any meaningful gameplay to it.