I think the rankings are as good of an indicator of the player of the year as anything. The only thing that conflicts with it is the Olympics because it isn't worth much points but is very prestigious, but if that is to be considered heavily then Murray needs to be brought into the conversation. Anyways, I'd say no matter what happens tomorrow Djokovic is clearly the winner of this year. That is not to take anything away from the amazing year Fed has had though.
I am a fan of Federer, Nadal, Djokovic and Murray. Yes, that's possible.