He let loose more at this stage in his career. I am not sure he proportionally let loose more according to team requirements though. He adapted according to team requirements in a general sense in terms of overall SR, but I'm not sure he adapted much according to specific match situations. His general best role ealry career was to bat slow, with the occasional change to batting quicker. Late career it would have been medium to fast.I agree that Kallis lacked the ability to accelerate based on match situation which is my main critique of him.
However, in that post 2008/9 phase, I do recall Kallis letting loose occasionally in a way he never did before in his career, especially in a few innings against Australia. He had quite a few cameo knocks in that phase when he would score in the 70/80 SR range.
You win games by scoring runs. You also win games (and series) by wearing bowlers down. Partnerships count. Seeing off dangerous periods counts, like the new ball or bad light etc. Assuming the same average, there are times when a SR of 0 would be best, and times when a SR of 600 would be best. Ppl who have a more balanced SR more typically represent the ability to do both, context dependent.What would be the issue in having a SR in the 70/80 range, assuming all other stats are equal? Yeah maybe you don't stonewall enough but you would be winning more games based on knocking the opposition down.
The only issue I could potentially see with the high SR is that it is not conducive for building bigger partnerships since your partner can't bat in sync. Sehwag for example has a few near double tons in which the team was bowled out in the 300s.