The thing about Roger Federer is this: my Federer is different from yours, despite obvious overlaps. This is true not just of great sportsmen, but great artists and musicians too. The matches and statistics are just a Google search away; the emotional connect to each follower is unique.
There are only two questions to be answered about Federer. Is he the greatest of all time? And, would he have been a lesser or greater player without the accident of playing in the same era as Rafael Nadal and Novak Djokovic, each a contributor to the legend of the other two?
Let’s settle the ‘greatest’ argument first. The requirements are simple enough. On the measurable scale, an all-round game, record, consistency, longevity. On the incalculable, aesthetics, conduct, ability to inspire and be the face of the game, respect for the sport but with a healthy perspective about its place in the scheme of things. You can add more. In the end, the judgement is subjective.