Maybe it is, but in my opinion it's all in the mind. He's got the game, just needs to serve better or more consistently. But he has to sort out his mind first. Also very interesting that he is aware that he needs to read his matches better against Fedal because he's too conscious of who is in front of him and that affects his gameplan.
"All in the mind" is a bit vague though isn't it? The Djokovic of late '07 / early '08 was a genuine world-beater, & although nerves got the better of him in his first slam final, he was capable of beating anybody on any stage & he proved it. It's a shame he didn't run into Nadal in U.S.O. '07 or A.O. '08 as he'd have blown him away & got that monkey off his back. It's a shame Fed had mono as Djoker would probably have beaten him anyway & Fed would have had no excuses. Back then, Djokovic was an intimidating opponent: controlled aggressive striking off both wings, superbly disguised changes of direction on his shots, great athleticism & flexibility in defence, a dangerous, varied, & above all, clutch serve, arguably the best backhand & return of serve in the game at that time; he was even volleying better. Ever since then, he's been little more than solid - kind of 2006 Roddick without the serve but with a far better backhand & return. He's been improving gradually but he's still closer to 2009 than 2008 & that isn't good enough.