I don't think AJs chin is that bad. If you fight enough top heavyweights you're going to get hurt at some point, it happens to all heavyweights.

AJ got off the floor to beat Klitschko and when you get hit in the temple as he did against Ruiz it is hard for anyone to recover. The 'visuals' of him being in survival mode for 3 or 4 rounds when he was basically done against Ruiz made his punch resistance seem worse than it is IMO.

I think AJ has a tendency to be open to the counter left hook when he is trying to finish guys (it happened against Whyte, Wlad, and Ruiz) if he can fix that he'll be hard to take out.

For me, Fury fights best when he has 'nothing to lose.' Nobody expected him to beat Klitschko or Wilder and he shone. I think he has the tools to beat Wilder (again) however he'll need to defend as the champion, with the target on his back for me to be convinced he's the real deal.