Roddick was must better on the USO and grass than the AO. Roddick pushed Roger to the limit many many times. There are different ways to win, not everyone has to rally like Nadal.
Running retrivers like Nadal, Djokovic or Murray seem to have the best chance to beat him.
Other ways are possible but difficult. Altough the highly aggressive groundstrokes of players like Tsonga or Del Potro also work sometimes. But certainly not every time.
And big servers never seemed to be a problem for Federer. Roddick was not. And present day big servers like Raonic or Isner are neither.