Joe had power for his size for sure , but look at the guys who he was knocking out , he was great in his time , no way does he beat either of the brothers grim its just stupid to say so.
Just the same as Marciano wouldnt beat todays top guys.
It doesnt mean they were not great in their own time, its just facts.
Jesse Owens was great , but against Usain Bolt he would look foolish.
Yes you can say who would win Ketchel or Hagler for example , because they fought at the same weight , comparing HW'S is just impossible.
The big guys who fought in Joe's time where generally bums or freaks, not top conditioned fighters.