Jaques Kallis has the best statistics of any cricketer of his generation, and yet if you did a poll around the cricket world amongst players, fans and the media to name the 5 best cricketers of the current era, I'm not sure that he would make it. I suspect the result, in no particular order, would be Warne, Tendulkar, Lara, Murali and Gilchrist, with Mcgrath and Ponting there or thereabouts. Which basically reinforces my point that you cant judge the greatness of a cricketer simply on numbers. The thing about comparing Kallis to his contemporaries who we have all seen play, is that we can easily explain why we rate the other champions in front of him. It might be the sheer genius of Lara, the technical mastery of Tendulkar, or Warne's ability to rise to the occasion and get the job done in big games when it really mattered. Either way it is easily explainable because we have actually seen them perform.
The problem with comparing Kallis to a legend like Sobers from a previous era, is that because most of us didn't actually see him play, all we have to judge him on are his statistics which never tell you the whole story. It is like looking at a 3D object as a 2D image. You might see some of the picture, but never the full picture. What is completely apparent, however, is that everybody who has seen Sobers play is completely in awe of the man, and is in no doubt that he is the greatest all rounder the world has ever seen, and daylight to the next guy.
There was obviously a genius, a freakish brilliance, and a match-winning quality about Sobers, that those of us that didn't see him play, will never fully appreciate. From everything you read about the man, he was a batting genius like Lara, a brilliant game changing fielder like Viv Richards or Ricky Ponting, and he had the champion's ability to rise to the occasion and perform great feats in big matches when it really mattered. Maybe his bowling average is a little high, but it is entirely possible that he had a champion's capacity of taking the big wickets at the big moments and had the ability to change the course of a cricket match with moments of brilliance, which is why his bowling is rated higher than his numbers would suggest. But, again, unless you actually saw the matches unfold and saw Sobers impose his will on the contest, you will never fully appreciate all of these attributes. When you combine all of these factors, you are talking about a sportsman whose greatness and impact on the game goes far beyond his mere statistics, which is why he is so revered throughout the cricket world.