kallis averages in the 30s in 3 countries
One of the 3 is Bangladesh, so convenient! I don't think there is another batsmen with 3 averages in the 30s against the top 8 in the 10k+ club other than Sanga. Kallis has got twice as many centuries in Aus+Nz combined which is basically the issue and as OS says, for that reason you have to take it with a pinch of salt.
Another double standard is how readily we accept Sanga's record in NZ despite him having last played there in 2006 but apparently his records in WI and India are misleading because he last played there in 2008 and 2009
Ditto with his Australia record. His Australia sample size is not much different from his WI sample size and the same as his India sample size(in terms of innings; he has actually played a match more if you factor number of matches). His Australia record is basically built on one innings in 2007. And that really is the problem. In places like SA and even England, he has played a lot more and his average is more meaningful from a statistical POV. He has played almost as many innings in SA as he has in Aus+NZ combined! And that really is the difference. Blokes like Kallis have toured far more often which makes it easier to rate them higher. For example Kallis averages 48.23 in Australia to Sanga's 60.33, but Kallis has played about three times as much and has 3 tons...for which reason I (and I suspect a fair few others) would rather Kallis' record in Australia to Sangakkara's.
Doing a country by country since it is what you seem to prefer:
1)Australia - Kallis for the reason mentioned above
2)England - Sanga
3)India - Kallis
4)New Zealand - Kallis (twice as many matches, again and Kallis' has hardly embarrassed himself there)
5)Pakistan/UAE - dead heat, same number of tons; maybe Sanga averages a few points more overall. Sanga
6)West Indies - Kallis
SA and SL excluded for obvious reasons. If you want to include them Sanga in SL and Kallis in SA(duh!).
Besides, Kallis has had multiple stellar series in the subcontinent..he has 8 tons in India/Pak+UAE....Sanga has 6 outside the subcontinent (and remember that means 6 in Aus, SA, Eng, WI and NZ included...5 countries).
In fact, forget the whole away from the subcontinent business. Even in the subcontinent(including UAE for the purposes of this discussion), here is how they go:
Kallis : 1677 runs@64.50 with 8 tons
Sanga : 1742 runs@60.06 with 6 tons
Forgetting statistics and everything even, how many would really back Sanga against really top quality pace or spin bowling in testing conditions? Please don't give me one innings played in 2006, Umar Akmal also got a century vs Shane Bond on debut in similar conditions as have others I suspect only to fall away later. And that was the reason I brought up Rahane only to get some smart arse reply as to how I was saying they were comparable as batsmen..I was not. It was a reply to the seemingly endless excuses the apologists have - he was a wkt-keeper...(abd has it) - oh but abd batted at 5...he played only 2 test series hence why he couldn't get used to the conditions (but why does this mean bowlers are inherently more likely to succeed in 2 test series and why then has Sanga failed to average well in a 3 test series EVER?)...but that is not the most important thing Ponting sucks in India (but Sanga has not done well in India either)..but Sanga last played in 2009....(how is it Rahane, Kohli and even Vijay are scoring centuries outside the SC from the get go)...how dare you bring up Rahane..Sanga's 10th highest score is better than Rahane's highest......and it goes on and on and on.
The way I see it, unless he goes to Aus and NZ again and shows that those performances were not one-offs it'll be hard to rate him highly. If he has 2 more good tours outside the SC then I'll be happy to concede he's got the game to consistently deliver in not so favourable conditions but otherwise he will always be below Amla and Abd, let alone Ponting, Lara, Tendulkar or Dravid.