Tennis is a sort of a duel, you don't have to be Hemingway to know, that the mano a mano aspect is relevant.
Tennis isn't boxing, stellar performance against a large pool of players brings the most success (tourneys, points, prize money etc.).
How much exactly "mano a mano" aspect is relevant is down to a personal opinion.
My problem with such way of thinking is that it basically means that if Fed was a much worse CC player (made one FO SF and never faced Nadal there for example), lost to Berdych at 2009 and say skipped 2012 AO he would have been a better player following that logic, there would be no argument over him being currently "the man of the era" because he would have had most slams, weeks at #1, winning slam final H2H against Nadal (2-1 in Wimbledon finals) etc.
Let's say Fed for example reaches USO final at the age of 33 and loses to Nadal there, instead of recognizing the feat of a player reaching a slam final in his 30s (something that rarely happens in modern game) we should be criticizing him for making his slam H2H with Nadal even worse and would have been better off losing in the 2nd round of the tourney to Joe the Journeyman.
If Agassi would be 20-14 against Sampras, one could make a case for him as the player of the 90s, even if Sampras has more majors.
Maybe but IMO it would be a very poor one in that specific example given the vast difference in dominance over the field during the the largest part of the decade.
Everybody would mention it, if Emerson would lead Laver 8-2 in majors.
Mention it yes but would it be enough to put him over Laver presuming Laver still won 2 Calendar Grand Slams?
In the case of Federer- Nadal and the player of the era, i would say, that the final evaluation still stands out.
Agree though it's mostly up to Nadal now, though Fed could still potentially surprise like he did at Wimbledon this year I'd say the chances of 2012 Wimbledon being his last slam title are higher than him adding to his tally.
At the USO 2010, i thought that Nadal - with his beefed up serve - could overtake Federer, that he potentially had more options in his game.
Nadal's 2010 USO's serve has become a bit of a myth on this forums, one of his best serving performances no doubt but for example he served better in 2011 Wimbledon final than 2010 USO final.
Since then, beginning with the AO 2011, Nadal struggled with problems and injuries.
He also struggled with injuries/form at the beginning of 2010 as well (though people forget that) but other than that Nadal was as fit as a fiddle in 2011 till 2012 Wimbledon.
Nadal's only problem in 2011 was Novak upping his game, other than that from 2011 FO to 2012 FO Nadal's consistency in going deep in the biggest tourneys was at an all time high, he reached 5 slam finals in a row which is his personal best, reached both IW and Miami finals for the only time in his career, reached Wimbledon final without going to 5 sets in earlier rounds (only happened in 2008 ), reached 7 finals in a row at one point (also his personal) best etc.
Djokovic got into his head.
It happens, Nadal's mentally as tough as they come but he's still human.
I reckon it highly, that he took this great mental obstacle by the horns, and this year reversed their head to head, before again falling out with injury.
Strongly disagree, all of his wins over Novak in 2012 came on clay, it would be akin to saying Fed overcome great mental obstacle against Nadal because he won against him indoors (heck, he bageled Nadal at WTF last year).
When both were playing well and it came down to crunch time at AO Nadal faltered mentally (missed an easy pass when he was up a break in the 5th IIRC).
Even at FO you could see Nadal starting to unravel mentally when the court become lower bouncing because of the weather conditions and Novak started to play well (IIRC he even threw the wet ball at the umpire or something) even though Novak's form in that tourney shouldn't have been good enough to challenge Nadal in the slightest.
At the moment Federer looks like the player of the era, but one doesn't know how Nadal will come back.
Sure, I'd say it's pretty tight, Nadal has a history of coming strong after injury layoffs.