Probably would struggle more with the big hitters like DelPo and Berdych. Prime Federer didn't have problems with the big hitters, because he was unbelievably fast on the court. He could ran out there all day like a gazelle. If his defense wasn't as good as Nadal, it really wasn't that far behind. His speed was never really the same after he contracted mono. Fast vs. slow court aside, Federer just hit the ball harder in his prime. His pace wasn't that far off from a Safin or 2003 Roddick, and you still had that ridiculous spin. Whenever he hit inside-out, he would easily run people off the court.