Their rivalry is unlike others in that one guy is always a constant, he's always going to give it his all and play his best against anyone on any surface, and the other guy has a game that is more about precision and timing and adapting his game to unusual opponents. Whether he's adapted or not I don't know for sure, but I do know that you cannot say Nadal has the advantage over Federer on any surface but clay just because he won in Dubai. Federer has made some real progress in their rivalry, and damn near turned it around in Rome, so their past results don't really matter as much now. Federer has completely changed his gameplan since then, so he's pretty much a different player now against Nadal.
Outside of clay, it's my prediction that Federer will rarely ever lose to Nadal again. On clay, it's a toss up.