Is the WTF worth 1000 ATP points ?
It can be worth 1500, but that's only if you win the tournament undefeated. The scoring structure is:
3 x round robin matches = 200 pts for win
semifinals = 400 pts for win
finals = 500 pts for win
Last year Roger won it undefeated, giving him the full 1500 points, but that isn't necessarily how it would usually go. From Wikipedia - Players who won the tournament undefeated (since 1990):
Michael Stich, Germany, 1993
Lleyton Hewitt, Australia, 2001
Roger Federer, Switzerland, 2003, 2004, 2006, 2010
So in other years the winner will have lost at least one of the round robin matches and finished with max 1300 points.
Nadal reached the 2010 final undefeated so is defending 1000 points
Djokovic and Murray each won 2 round robins, then lost in the semis (no points for losing) so they're both defending 400 points.