What you said about the tactical aspect of it is true, yet with virtually the same game plan, Fed dropped two sets at the AO. I've also lost count of how many times he went out, looking dominant in the first set only to fell back into Nadal's rhythm and promptly lost the match.
He also said it himself before the match that he'd keep 'play free'. Even us fans are mentally scared from how many times he've lost, hard to imagine it didn't affect him in their past encounters.
Also, even with the current resurgence, Nadal is still physically a notch or two below his peak. When he was in his peak, he covered the court like no one else I've ever seen and it's mentally and physically draining to play against an opponent you know will get to your shot 8 or 9 times out of 10.