I see it all the time on here:
"Federer only snatched so many titles because the players were weak during 2003-2007. The fact that he later had a trouble with Nadal and Djokovic, eventually losing his #1 rank to them, proves this."
What a ludicrous argument!
First of all, in tennis, as in any sport, the level of play is always improving (I guess "level of play" would have to be measured by average speed of groundstrokes and serves, physical fitness of players, and a few other metrics). The game gets more competitive at every level, every year.
Second of all, the fact that there was a greater variety of finalists to face Federer in 2003-2007 does not mean he had it easy. The guys who made it to the final in a given tournament were on fire during that tournament. Just because they weren't on fire as consistently (á la Nadal or Djokovic) does not mean they were any less difficult to defeat when they were on fire. (Say it were true that the same 2 or 3 Rookie players always showed up in the final match, while the Champs tournaments, on the other hand, always seemed to have a different set of players in the final. Would that mean that Champs is less competitive?)
Third of all, Roddick, Safin, and the other supposed "light weights" of yesteryear were not in fact lightweights. Roddick was hitting 25 aces per game and successfully charging the net off his forehand. Against a prime 2003-2005 Roddick on a 2003-2005 hard court, Nadal got whooped, and I bet Djokovic would've too.
Fourth of all, the fact that Nadal and Djokovic, both of whom originally had trouble against Federer, were eventually able to crack him (when he reached age 28+), does not mean they are better players. But suppose it does mean that. Then we can apply the same argument for any player, since they all reach a state of permanent decline at some point (Not to say that Federer has reached permanent decline). "Player X used to beat player Y, but eventually player Y started to beat player X. Therefore player X was never better than player Y; he only was able to beat player X before player X had reached his full potential."