Man, I never hear about him when talking about all time greats. IMO, he deserves to be in top 15. To me, as player, he is better then Lara, Ponting, et al. He has shown that he can play on seaming tracks (record in SA) and spinning tracks (record in subcontinent).
He is also very good with the ball. Has > then 500 international wickets.
Yes, I know he is lot better against bad teams but so are many other greats but this guy is also amazing with the ball.