I'm pretty sure he won't be. he's obviously not getting any closer nowdays - as Murray passed him in the rankings. He certainly has the game and talent to be #1, but I don't think he's mentally up for the task, not to mention his questionable fitness. You just never get the feeling of domination when Djokovic is playing. Not the feeling you get when you watch Fed or Nadal.
I wish him all the best, despite the fact I dislike him.
Murray, IMO, does have the ability to become #1, but he has much to prove before that happens.