After Djoker's late 2007, early 2008 run up, very few people predicted that he'd be slamless till 2011. Then he blew away 2011. He could very well cool down in 2012 and so then have a standout 2013 or 2014. My point is that once you have proven: 1) The weapons to hang and beat the top guys 2) The mentality/self belief to hang and beat the top guys then you should always be a threat until you significantly decline physically. There is a saying in cricket "Form is temporary, class is permanent". Also this is also not the first year he has overplayed and been tired by the end of the season. So I'm inclined to think that what he does in 2012 is not necessarily an indication of the future. Of course to be fair it also depends on the form factor of Fed/Rafa/Murray do. Outside of these 3, I don't foresee a newcomer or someone like Tsonga coming in and being top gun. If Djokovic doesn't win at least 4 slams in the next 4 years it will be because a) Fed reverses aging and has some crazy renewed desire to win slams b) Nadal tweaks his game to improve BH and serve c) Murray finally discovers self belief in slams.