If you really think about it, there's no real point in him making the trip to South Africa, we're not going to win (the series), simple as. I rather take one of our countless number of promising young batsmen(preferably Rohit Sharma or Manoj Tiwary) and watch him get shat all over by the South African pace attack, all in hope that he learns from his experience.
Wouldn't mind that tbh, maybe then we'll finally get a competitive match going between the two teams.
As bad as Ashwin was in Australia, he still out did his predecessor by quite a bit.
Ravichandran Ashwin in Australia
Harbhajan Singh in Australia
But you're right, he has to perform overseas and SA would be a good place to start doing so.