Sure, Roger Federer has not been quite so magnificent this year as he has been these past three years. Defeats to Canas (twice), Nalbandian (also twice) and Djokovic in Montreal have dented his air of effortless (non-clay court) supremacy. But, seriously, how can you write an article with the headline "Federer's Ability to Dominate May Be Coming to an End" without mentioning that he won three of the four Grand Slams this year (and reached the final at Roland Garros too)? The only reason to think that he's not quite as good this year as he has been in the past is because of the absurd standards he set in 2005 and 2006.
In any case, the point of Roger Federer can't be measured by counting titles. It's all in the way he plays the game. No-one has ever been quite this brilliant while playing with such style. Watching Federer play tennis is an aesthetic pleasure that can legitimately be considered an artistic experience. For chapter and verse on this, see David Foster Wallace's excellent hymn to Federer from the New York Times last year.