Aye, not now, but they could be. If a champion can do all the stuff that saved the world from Oblivion, changing the form of government shouldn't be too difficult.
Not true. The "hero" usually comes from obscurity and goes back into obscurity pretty fast and uneventfully. The Nerevarine was a prime example of a potential politically massive figure who got squirreled away into the obscurities of gossip and idle pvssyr.