Just the fact that he's been the most consistent, he's won seven titles and been to all nine finals since his return. His serve looked really good in Paris, which is going to be big for him at Wimbledon, especially if he plays Djokovic. I think he's a better mover on grass than Djokovic. Djokovic hasn't really ever learned that you don't slide on grass, you slip. But he's so fast and excellent a ballstriker that he can get away with it.
Federer's light baby steps make him the best mover on grass, but he's looked pretty awful this year by his standards. Two really bad losses to Nadal, fading in the fifth set to Murray, losses to guys he shouldn't lose to, only one top ten win all year, I mean, he has work to do to make me a believer. He's almost 32, his days are numbered. The last two years he was playing phenomenal tennis going into Wimbledon, and last year he controlled his own destiny to reclaim World No 1. He has not playing well in 2013 and has no such motivation.