If this PotY is about titles and finals and runner-ups and all that jazz than let the GS+MS+OLY points in the Race standings decide the player of the year. I'm thinking this is a bit different than a results draw-of-the-line. A combination of quality tennis played + popularity/fans raised + sportsmanship + results should do nicely.
QUALITY OF TENNIS:
Djokovic and Federer each share their contribution in the first part of the year, with beautiful matches and very well organized games. Of course Nadal takes the second semester showing off his best part of the year. Federer and Murray take the third semester (great matches both in Wimbledon and the Olympics), while US Open showed Murray and Djokovic not with their best tennis, but pragmatic nonetheless, Federer also pragmatic and not at his best, but a bad day was enough to cast him out. I choose Federer as the player with the best quality tennis so far this year (although things may change).
It's clear to me that Murray has the best contribution here. He improved a lot this year and many people have come to admire this, although I can say that the opposite also took place for a few other people, which is normal in such cases. Federer's scores second due to records being broken, which is attractive, yet, due to the quantity of records already broken, the impact is not as high as Murray. Djokovic and Nadal didn't score much here.
I wouldn't say that any of the big 4 score big time here. I'll let this undecided for now.
Djokovic should be the better player here with the most constant good results in Grand Slams. Murray's Gold Medal vs Federer's 3 Masters is probably the most disputed argument for second place, but we're looking for the best player.
So, it's a tie. 1 category for each of Djokovic/Federer/Murray, with Sportsmanship being the decisive point. I shall ponder this.
That's my POV for now.