Let's look at the top 4 men's players (and I'm going to be historical and call them "The Gang of Four" rather than whatever cutesy name tennis writers like giving them) and see where they might have problems in maintaining their rankings next year and where they can pick up points.
I'll throw in the Olympics caveat, as it offers 800 points to the winner, but comes when a number of players are beat up in the summer.
# 1 Djokovic
End of year point total: 13,630
With so many titles, there are few chances for Djokovic to earn more ranking points (a final/win at Roland Garros, winning Cincinnati or Paris, playing Shanghai or Monte Carlo). He's going to have to defend like crazy, and I'm not sure it's possible to have as good a year as he had again.
#2 Nadal
End of year point total: 9,595
Nadal can improve his ranking if he can beat Djokovic and do it often. Otherwise, he's going to be defending his #2 ranking. Shades of Federer 2009, he had the best claycourt season with a slam and a Master's despite someone else being the massive favorite with 2 Master's heading into Roland Garros. Nobody but me will harp on that fact. If he can't beat Djokovic in finals and Djokovic makes it to those finals, then look for him to maybe pick up points at the Australian Open. Nadal could pick up a number of points after the US Open, but he's traditionally been bad at that time of year. I don't see that changing.
#3 Federer
End of year point total: 8,170
He had a great end of the year, but 5,170 of his points came before that. He had "only" 6 finals this year, but he's going to have to figure out a way to consistently get past Nadal or Djokovic off of indoor carpet if he wants to be in the top 2.
#4 Murray
End of year point total: 7,380
He needs to not fall apart after the Australian Open, whether he makes the final or not. He did better than Federer at the slams and made 6 finals as well (with more titles, 5 to Federer's 4). The post-US Open Asian sweep was where he made a lot of his points. He has traditionally played very well during the period inbetween Wimbledon and the US Open, giving him Olympic hopes. He also has the "can't get higher if I can't beat Nadal or Djokovic in the semis" problem.
