Pretty much every variation of an athletic body type has won a WC dh race several time over. Me thinks you're over thinking it.
Especially when so much of the difference between 1st and 20th is above the shoulders.
Totally agree about the interesting variety of body types to have been successful in WC DH over the years. But you know, that has also really leant to my "what the hell are these guys doing" perspective. DH has been a skill & confidence driven sport all along. It still is, no doubt. But now WC DH has a guy with a ton of confidence & skill who's also properly conditioned for the sport. I predict Gwin's involvement in the sport will change the way top guys (and eventually everyone serious) trains.
It's a good thing, part of DH becoming a grown up sport. Think of any mainstream sport 50 years ago. The whole "different body types can succeed" line of thought used to apply a lot there too. But time and money always narrow down a sport's parameters for success, and we end up with super specialized conditioning techniques.