But I think the biggest difference is he just didn't miss, no matter how long the rally or hopeless the position. Now its common to see Fed lose the point with an error, or hit a weak passing shot attempt straight back to the guy at net. This never used to happen.
You and I used to watch different Federers then. I used to see him shank and make unforced errors all the time. Are there any statistics available out there? I'd love to compare his unforced errors over the years. I doubt he averages much more now than he did 6-10 years ago.