Still only second best.
Dragonborn status literally means you have blood or status equal to Talos himself when he was the first emperor. that isn't a claim to just Skyrim, thats a claim to the entire Cyrodilic Empire, since the last person with any blood relating to Talos was Jauffre, and y'know what happened with him. The Medes have no blood relation and the whole magic that the empire ran upon to keep out the the daedra in Oblivion was the dragonborn bloodline descended from Talos. Basically? the Dragonborn has the potential to be a second Talos and bring the Empire back to being strong again, thats a lot more power than just Skyrim from a cynical political perspective.