In the previous seasons Djokovic has been the hunter, trying to chase down Federer and Nadal, but this season he was the hunted right from the start. He handled that pressure very well.
I wouldn't be surprised at all if he is more relaxed next season and has become more accustomed to being the 'marked man' and biggest scalp and target on the tour, and goes on to have an even better year in 2013 than he had this year.
I think Federer said something similar that when he backed up his first great so well (in fact with another great year in 2005), he found the pressures and burdens of being the world no. 1 and main man a lot easier to handle and more rewarding.