Is Haye's Punching Power at Heavyweight Massively Overrated?

By pointing out that he was knocked out by Tua? And by saying that Ruiz avoided heavy hitters without backing it up? I would not count that as "proof". It is just an opinion.

 

So after 55 fights as a HW he was knocked out cold only once (David Tua), stopped once (David Haye) and had some downs he got up again after?

Iron chin? Maybe not? Good chin? Defenitly. Bad chin? No chance. You underestimate the punching power a HW have to face.

 

Ruiz does not have an iron jaw (or temple for that matter). Tua took him out in 19 seconds, Holyfield badly hurt him in round 3 of their first fight with one punch, Roy hurt him badly in the fourth fight with a well-timed right hand, Golota dropped and hurt him in the 2nd round of their fight.

His chin wasn't glass, but wasn't great either.

 

No, there is no evidence that proves he has an iron chin. But the opposite is true as well. There is no evidence for him having a weak chin either.
The he-never-fought-a-big-punsher-argument is frail. Did he duck Samuel Peter and the rest, or did they duck him? There is, however, two things that suggests (don´t prove) that he has a good chin.

1. He has never been hurt to the degree he was by Haye.

2. He is huge.