It was pointed out that the extremes of the graphic were based on small sample sizes so obviously the skew might be exaggerrated for Djoko there.
I think the points brought up in the article were much more interesting than the graphic. Djokovic tuning his game in for control and having bigger margins compared to Fedal, but that puts him at a match-up disadvantage against a certain type of players. Whenever we'd talk here about how complete a player is, Federer's one-hander would be brought up without fail as a stroke that made him vulnerable, even if 99% of that vulnerability was against Nadal on clay. Very rarely was anything along the lines of "With his more extreme grips and board-like frame, what Djokovic can struggle with at times is generating pace or being dynamic off low and slow balls, and this is exactly the kind of player he sometimes struggles with" mentioned. Apparently that can also at least in part explain why he has a worse record on very slow courts.
To my mind, from a visual non-technical angle, Federer's game always seemed the most balanced and versatile, suitable for different conditions and different opponents (with the single major exception). This article kind of enforces that view for me.
