I think you're on to something! Although I would include GN'R as a group for some of the highlights:
Tyson: Mike was a heavy weight and a small one at that. He was a truly an all around fighter, not just a puncher. And though most experts say Muhammed Ali was the greatest, I believe that in his prime Mike Tyson was the most fearsome and devastating fighter ever. The original Mike under Cus D'Amato was unstoppable.
GN'R: They really had no musical peers when they exploded with Appetite For Destruction. People usually pick The Stones, or Aerosmith or some other heavy weight as the greatest rock band, but again, in their prime no band was as fearsome and awesome as GN'R.
Tyson: Moving forward Mike became the biggest celebrity fighter of all time. More so than Ali, Frazier or Foreman. The biggest. He lost Cus and started losing touch with his humble roots. He got in trouble with the law and started losing fights (i.e. KO by Lennox Lewis). He then retires on the downswing.
GN'R: It goes without saying that they became the biggest band in the world, overshadowing the greats that they formerly opened for. 'Illusions' showcases the band's vast musical abilities further separating them from other groups. They started having legal trouble-domestic for Axl and riots for the band! They lost founding members Izzy and Steven and with it, their street-wise roots. The commercial let down of 'Spaghetti' is a blow that they don't recover from.
Tyson & Axl: Both go through a period of being out of the public eye. Both emerge with a new look and a noticeably calmer demeanor. Both go on to redefine their careers with positivity and both with the occasional stumble. Both are still bad-ass!
Whaddaya think?