You want to see some serious beat downs, check out some of the results in the qualifiers of futures and even the main draws. A kid that used to be ranked top 10 in the country in Boys 14's, who recently got to the semifinals of singles and doubles in Boys 18 at the Zoo, lost to UCLA's number 6 singles player Michael Look 6-1, 6-1. Look beat some other dude 0 and 0. And the guys in the futures qualifiers are generally 6.0 and higher.
Or go to the US Open qualifiers. I watched Kevin Kim, fresh off his second dominant NCAA season, get beat 1 and 1 by Jan Vacek. In some of the pro qualifier tournament, you see some true beat downs being handed out to guys with ATP rankings by guys who would struggle to win a few games off Fed.
Even the whole "I'll go for aces and winners" strategy, what might be a winner against your friend isn't going to be a winner against the local college star, let alone a pro ranked in the 500's, let alone Federer. Fed is used to playing successful defense against guys like Nadal, Verdasco, Roddick, and Davydenko. Plus, you're striking these winners off shots that don't have the same precision, action, and speed of a Federer ball. Same thing with "aces," what might be an ace against one person is a sitting duck for another person. Fed routinely faces incredibly precise 130 mph serves hit by guys with very deceptive and smooth service motions.
Again, go watch some qualies to see what kind of beat downs happen. Lots of bagels being served in those draws. To really good players. I think people are seriously underestimating just what it means to be talked about as the best player of all time. His regular body shot, his warm up ball, is going to come at you faster and with more action than anything you've ever faced.
Most of us would barely win points against a guy ranked 900 in the world. He, I see some John Patrick Smith of University of Kentucky is currently 982 in the world. He's ranked 3 in the country in NCAA singles. Go win some points off him, see how easy it is.