Are you sure?
I'm pretty sure that if the ruler abdicates willingly, it's quite different than if he is defeated. I'm not sure for what aspects, though. I know you can't reform the government if he steps down, and I'm under the impression he isn't auto-banned either, and wouldn't be surprised if he kept his royal title.
I can speak first-hand about abdicating during a rebellion. You get instantly banned and declared a rogue, and by extent lose your Royal status. Once you know you can't win it's basically a fast-forward button to the end of the rebellion.
