i think you're opening up a can of worms. are golfers world class atheletes? because i'm pretty sure lebron couldn't practice golf for a year and be a dominant golfer. what about divers? i mean they just climb up a ladder and jump into a pool. are they world class atheletes? could lebron practice their sport for a year and be one of the best?
I don't really know. case by case basis, I guess? I'd say athletic ability is combination of physical prowess and also skill. To me, a gymnast is the gold standard. then I work down from there. I'd say that Tiger is a worldclass athlete b/c he's f'n jacked is also very skilled. Is Phil bitch-tits Mickelson also world class, athletically? I want to say no, because whiel incredibly skilled, he doesn't appear to be much more physically superior than the average guy on the street. Divers are basically gymnasts + water, so I'd say they're world class.
Looking at volleyball, though, I see the skill set as being very similar to basketball. I think many NBA bballers could play volleyball professionally, not the other way around. Therefore, as I consider NBAers world class athletes, I necessarily can't view volleyballers as world class too. Clearly, one class is superior to the other class, IMO.