Nole had more of an "off year" this year but he picked things up post USO. That could very well carry over into next year. He played so well in 2011, that it was only natural that could have affected his play this year.
Nole is the heavy favorite in Australia, and if Nadal isn't back at top level by clay season, he will be the heavy favorite there. Wimbledon and the USO are question marks but not out of the realm of possibility, Nole could win both.