Race ranking this early in the year is not very indicative, but maybe it is worth noting how the semifinalists stand right now:
Andy Murray 133.3p 10m
Novak Djokovic 121.4p 9m
Tomas Berdych 121.4p 10m
Stanislas Wawrinka 121.2p 12m
Murray is in the lead, Djokovic and Berdych are tied, and Wawrinka is neck and neck behind.
But Djokovic has fewer matches played.
According to Elo expectation numbers, favorites for the final are Murray and Djokovic.