I don't know if he was ever an out and out serve volleyer or just an all court player with the ability to play serve volley...like say Bjorn Borg. Even in 2003, he played Roddick from the baseline but went S&V in the final against Philipoussis. Yes, the difference in the way Nadal, Djoko play is they hit very heavy and keep at it relentlessly. That is not really Fed's forte though he has tried admirably well to keep pace with them at that. He is more about amazing wrists which he uses to suddenly and unexpected change direction and stun the opponent. Speaking of slow courts, if you watched the Llodra-Murray match, you wouldn't notice it. And I can swear I didn't when I watched the Rafter-Ivanisevic Wimb final in 2001 (when the courts were supposed to have already been slowed down). So it's also about racquets and their impact on playing styles. Even if courts were as fast today as in the 90s, the racquets by themselves would give players more options and put incoming volleyers at greater risk of getting passed. This might be unpalatable for old school tennis fans but this is just how tennis has evolved over the years.