I think he should have 1-2 more slams (one more from this year and one in 2009 or 2010). But he has a chance to make up for it.
He blinked in the 2007 US Open final. Fed couldn't wait to tell him how brutal he lost to his brilliant self.
Djoker was hungry after the 2008-9 lapse period. Media & players' hatred actually brought him more wisdom.