Just like I said Federer is the one turning his rivalry with Nadal around in his favor, not vice versa. Nadal was once 6-1 vs Federer, now that once large lead has dwindled to 8-6, with Federer going 5-2 vs Nadal in their last 7 matches. Nadal won 2 of his first 3 matches with Federer on hard courts, and Federer's only win took a full 5 sets in a best 3-of-5 after losing the first 2 sets. Their last 2 matches on hard courts however Federer won in straight sets, and their last match was Roger's easiest win ever.
To break it down closer, Nadals first 7 matches with Federer:
2004 Miami 3rd round- Nadal defeats Federer 6-3, 6-3
2005 Miami final- Federer defeats Nadal 2-6, 6-7(4). 7-6(5). 6-3. 6-1
2005 French Open semis- Nadal defeats Federer 6-3, 4-6, 6-4, 6-3
2006 Dubai final- Nadal defeats Federer 2-6, 6-4, 6-4
2006 Monte Carlo final- Nadal defeats Federer 6-2, 6-7(2), 6-3, 7-6(5)
2006 Roma final- Nadal defeats Federer 6-7(0), 7-6(5), 6-4, 2-6, 7-6(5)
2006 French Open final- Nadal defeats Federer 1-6, 6-1, 6-4, 7-6(4)
now Federer's last 7 matches with Nadal:
2006 Wimbledon final- Federer defeats Nadal 6-0, 7-6(5), 6-7(2), 6-3
2006 Masters Cup semis- Federer defeats Nadal 6-4, 7-5
2007 Monte Carlo final- Nadal defeats Federer 6-4, 6-4
2007 Hamburg final- Federer defeats Nadal 2-6, 6-2, 6-0
2007 French Open final- Nadal defeats Federer 6-3, 4-6, 6-3, 6-4
2007 Wimbledon final- Federer defeats Nadal 7-6(7), 4-6, 7-6(3), 2-6, 6-2
2007 Masters semis- Federer defeats Nadal 6-4, 6-1
The difference is fairly obvious. Nadal goes from having the edge on hard courts to being increasingly outclassed on hard courts in recent meetings. Despite now being a stronger player on grass now then he ever was on hard courts, Nadal cant beat Federer on grass when he used to be able to beat him on his now worst surface of hard courts. Even on clay Nadal takes his first ever defeat to Federer.
Now their 5 matches on hard courts only:
2004 Miami 3rd round- Nadal defeats Federer 6-3, 6-3
2005 Miami final- Federer defeats Nadal 2-6, 6-7(4). 7-6(5). 6-3. 6-1
2006 Dubai final- Nadal defeats Federer 2-6, 6-4, 6-4
2006 Masters Cup semis- Federer defeats Nadal 6-4, 7-5
2007 Masters semis- Federer defeats Nadal 6-4, 6-1
So Nadal goes from dominating Federer their first meeting, losing a match he should have won in straight sets in the second, winning a match he should have lost in straight sets in the 3rd, losing a match in straight sets in a 4th, then getting clobbered in straight sets in the 5th.