I think William's link he posted from the ATP site is also very revealing. Both Federer and Berdych played an aggressive game and were able to have great success with it, especially Berdych who over the course of the tournament has put a beat down on far more defensive players. It's also telling that the two people who gave Berdych trouble (Del Potro and Federer) and those who gave Federer trouble (Raonic and Berdych) were both fellow first-strikers.
I don't quite trust that serve and volley is the way to go on any surface anymore. As a surprise tactic, yes, definitely. Very few folks have the kinda serve required to serve and volley. And I'm not talking just pace here, the kind which most players these days like Berdych and co. can produce in the 140mph ranges. Gasquet throws in a mean serve and volley when he feels like it, and I'm glad to see Federer taking a stab at it with good results. Should be an inspiration for others to try.
That said, I would think that serve and volley might sometimes be a better option on slower surfaces than quicker ones as the server will have more time to set-up at the net. coupled with the right serve, that's dangerous. Without the extra time on faster courts the server might not be able to get up to the net comfortably enough and might be forced to hit awkward half-volley's from behind or around the service line, or simply get passed by better returners who can step in and take a stab at the ball and redirect it as it skids towards them. And a less than stellar half-volley is pretty much a point lost these days when it comes to taking the net.