I don't think Roger Federer still has anything to prove in the men's game. Maybe win the Olympic gold in men's singles! Anyway, as we head towards another Grand Slam, I always have this thought at the back of my mind, that if the draw just opens up a bit with an upset of a top player, here and there, Roger would be able to win Grand Slam title #17.
It may be possible to do it in this year's French Open. He will only first face real competition by the fourth round, possibly through Feliciano Lopez. Tomas Berdych will most likely be his quarterfinal opponent with Marin Cilic, the closest other possibility.
He should face Djokovic in the semi-finals. He has to fight harder to defeat the in-form Djokovic, but if he does, Nadal should await him in the finals.