Highly unfair on Ashwin that people pass judgements on him after a 5-6 tests, out of which he has got a bagful of wickets in three of them. It is not his problem that West Indies could not withstand him in India. And in fact, WI were coming into that series with subcontinent exposure where they had played Bangladesh just before that series.
Ashwin needs to attack more, and he will do that when he hits subcontinent wickets (and hopefully on his next overseas tour too after his first tough experience). And his batting is highly reliable (he has a test century too) so he doesnt lose out to Harbhajan on that. Harbhajan has experience, but Ashwin needs to be given that to see how the two compare.