Regarding Dorian's unique granite like appearance...
I've heard people touch on it but 80% of it comes from genetically
incredibly thin skin. Most of the pros knew of this and even Yates
doctor realized this.
Black people in general tend to have thicker skin than very white/pale people.
The pale boxer/fighter tends to cut easier whereas the black boxer tends to
swell when the white fighter would be bleeding.
Of course there are always exceptions but I am speaking in generalities.
Ronnie has thin skin for a black man but has thicker skin on his back than Yates does.
Ronnie has incredible separation/striations which is also genetic.
One unique trait Ronnie had; Samir and Arnold had the same trait also at their respective bests...
He goes from looking semi cut relaxed or in transition, to a striated anatomy chart when he posed/flexed.
There is also a greater illusion (than other bodybuilders) of growing before your very eyes when flexed. (As Ronnie got bigger this trait was not as profound as in 98,99 and 2001AC.)
Arnold always held this bodybuilding trait in high regard.
This is possibly one reason why Ruhl did not fair better than he did. Even in that great 2002 video
everyone raves about there is not that huge difference between him walking out there
and when he poses.
bodybuilders call this phenomena 'pop'
and and for the racial disparities you commented on, i dont know about thickness, but i could kind of buy it.
but black guys when completely dieted down, when compared to white guys completely dieted down......tend to carry more water (not fat, water)
that is why all the BBs in history famous for getting shredded and grainy are white (gaspari, munzer, yates, paco, jay at times, ect)
and most of the great black bodybuilders have always been knocked for carrying a film of water (flex, melvin, tony.....ronnie was kind of an exception, thought he washed out at times too, but it mattered less because he was so damn huge compared to everyone else)