The op is right. There is a clear difference. I think, all the praise and hype got into Federer's head. Despite all his talent, he laid back, stuck with the smooth reluctant game, and he had success with. This worked for a while. But ever since 2008 the writing, speak Nadal, was on the wall, and Federer stagnated, since he fired Tony Roche in 2007. Now it could be too late, to implement more volleys into his style. Its a matter of mentality, you have to believe in it, to go for it in matches, even if you lose some. Steffi Graf never handled the topspin backhand in matches, although she performed it well in training.
Nadal is improving, implementing new things, altering his style of play, even with the risk of losing some matches. One word to this crap about bad matchup. I for myself exspect of the best player of all time (whoever it is), that he gets rid of an opponent, of every opponent, on any surface, under any conditions. Exactly this makes him the best.