"Body shape" isn't what people usually mean by 'talent', and I doubt you define it that way either; but if you want to define talent to mean body shape, I will happily concede that talent is important.
You said
>The major difficulty with the idea of "natural talent" is that every time someone points to a skill/whatever and says, "this is natural talent" someone else finds a way to teach that skill.
Can anyone be trained to run as fast as Bolt or would they have to be naturally talented in the first place to be trainable?
"Talent" is usually a catch-all for innate features distinct from trained features. ("Body shape" has both innate and trained elements.)