Fed had already been straight setted at AO by 20 year old Djokovic and had lost badly to Murray at Dubai and Fish at IW. He even lost to Roddick in Miami, all of those happened before he played Nadal that year. Other atrocious losses (if we don't want to classify Wimbledon 2008 as atrocious) include Stepanek at Rome, Karlovic at Cincy, Blake in straights at the Olympics, Simon twice and Murray an additional two times as well. That isn't all or mostly down to Nadal, it was an enormous drop off in play before and after RG 2008.