Are you really trying to say Federer has benefited from grass slowing down? How does a fast court player benefit from a court slowing down? How does a does a player who prefers low balls on the backhand benefit from higher bounces?
Look, I agree with the argument that fast HC and grass needs to be restored to its roots. Also, would be nice to have the fast indoor season back, smaller than the other surfaces sure, but at least a swing in the carpet would be nice. As far as this argument goes, Federer did benefit from the slowing down of the surfaces at the time it came. Federer can be considered a fast court player in the current crop, but rewind to 2002 and he would be considered a mild aggressive player at best, he did not have an aggressive style such as Sampras, Philippoussis, Henman or Agassi, from a baseline stand point. These guys apart from Agassi, would all look to finish points in less than 5 strokes, while Federer, never really minded getting into long rallies.
Matter of fact is Federer's style has always been a mildly agressive baseline player. Sure, he has great variety and is able to mix it up serve and volley specially in the early 2000s, but he can not be considered a fast court player by the standard of the 90s. So the slowdown of the grass in 2003 benefited Federer as he was able to get much better look at Philippossis, Roddick and others serve and make his aggressive baseline play work on grass and is good to remember, that Federer was one of the first guys, along with Hewitt in 2002, who began the trend of being able to win Wimbledon primarily from the baseline. It began well before Nadal or Djokovic.
Now, forward to 2012, Federer's game nowadays of course, suits better in faster conditions being 30 year old, who developed his game in 90s decade using classic grips, in this Western grips land of today, also having beefed up his serve significantly, he can be considered a fast court player, just like a player like Haas can, but Haas also could barely enter the category of an aggressive player by the 90s standard. So the speeding up of the courts would probably be beneficial to Federer now, specially with his top match ups like Djokovic, Nadal and Murray. But is good remembering that guys like Isner, Karlovic, Fish, Roddick etc. in a hot serving day with the grass of the 90s, early 00s could make the match a lottery with anyone. Would Federer have won as many Wimbledon's as he did, in a super fast grass court with guys with the serve such as Roddick, Karlovic, Stepanek bumping around the draw? That is where Federer benefited also from the slow down until a certain point.