One of the better posts I've read on this forum in a while.
Nadal has the "talent" having a great body, without doing a lot for it (uncle Toni often says Nadal has never really been fitnessing a lot). Another "talent of him is how relentless he is and how can stay focused for 5 hours without a single blip in concentration. Those other talents than being able to hit the perfect BH or FH or serve, but they are equally useful in becoming a pro tennis player.
what Duong was elaborating upon was the fact that Nadal's groundstrokes themselves are very talented- there is a reason no other players on tour can really emulate him and hit the ball like he does; he grew up with a very unique style with extreme spin and it a very talented way to play. no one can do it because it is not easy, maybe partially due to the hard work needed, but also due to the just natural talent it takes.
this is often taken for granted, people criticize Nadal as a hack often who relies purely on his athletical prowless, yet he plays a style (and I mean as far as his groundstrokes, point construction, etc) that no other players can do in today's game or in the past. he is unique and full of talent