I used to have this great article that explained Nadal's congenital foot problem. It seems that he was born with it and it's something that should have been corrected in childhood. But, what parent checks every bone in their child's body looking for defects? It was either soon before, or after he joined the tour, that the defect was made known to his parents and he was advised that he would never be able to play full time on the tour.
His parents searched globally for someone to help him with his condition. They got advice from the best in the world and some help from Nike who makes him special shoes (not the erroneously reported, he had to wear his shoes two sizes too small concocted by the commentators). Because of the location of the bone it wasn't possible for him to have the bone re-broken, instead they had to make adjustments around the bone.
The problem is that because of the position of the bone it puts unnecessary pressure on the knees which causes both pressure and pain.
At this point, the Nadals are faced with a difficult dilemma; does he abandon a promising tennis career, or play as long as he can? They let Rafa decide and he chose to see how far he could go. I think he made the right decision, but he has to do it his way.
All of the talk about playing style is, in my opinion, unfounded, much like the "two sizes too small" story which was fictictious.
So, what are the alternatives? To play less and find yourself always playing catch up? Coming back with harder draws and opponents who could further delay your progress?
Sometimes you have a condition that can't be helped and you have to work with it, rather than against it.
Not only that, but you have to take the player's personality into account as well. Rafa is said to be pretty hyper, always in motion, so I don't think that resting will work to his benefit, because it's against his nature. He has to do what works for him whether the fans understand it or not. I think it's a case of mind over matter.
I say that because I have a friend who is disabled. To see her, you would think that there's nothing wrong with her, and when she catches the bus and asks the bus driver to lower the steps, the bus driver and the passengers give her dirty looks. But the truth is, she has fibromyalgia, a thyroid problem, and nerve damage, amongst other things. She never has a day without pain, but she refuses to give in to her physical limitations. That's due to her mindset. I couldn't understand it at first, but now I see what she is talking about. You can allow a condition to overtake your life, or you can take over the condition. There are psychological ramifications to giving in to a condition.
This is just my opinion, but I can't see Rafa being overly careful and imposing those limitations on his own mind. He wouldn't be the competitor that he is if he didn't have his mindset.
The Nadal family was already wealthy, so money couldn't have been the issue. It can't be for the glory, because it's obvious that he doesn't feel that way. It's of no benefit to Toni, because Rafa doesn't even pay Toni for his services, so the only thing left is Rafa and his desire to compete.
And me, I'm glad he chose to play.