Plus I want to stress it again that Fed would be using better racquet all of his career which would help him at FO. Also, given that Nadal would be the number 1 player in 2005-2007 Fed would focus his training in early years to compete with him instead of guys like Nalbandian, Hewitt, Roddick, Aggasi, Henman etc. I expect starting from 2008 Wimbledon Federer would have emerged as the new number 1 and owned everyone (except maybe Nadal on clay) for the next 5 years straight.