Nadal was lucky that Federer played his best match of the year in the RG's semifinals 2011, otherwise Nole would have got his first RG in the bag. Of that I'm certain.
But maybe not Wimbly, who knows...
It would be emotionnaly hard for him to win both back to back, even worse considering he would still be undefeated with a considerable pressure on his shoulders. (He was flying under the radar before Wimbly 2011 even though he had lose only one match this year, Federer and Nadal were seen as the join favorites)
It was probably better for him to win Wimbly rather than the French this year, he has a much greater shot on clay in the future than on grass imo, but Wimbly is already in the bag, good for him.