I would have had Rahane in the side if it was a tournament held overseas. But to me, Rahane is another Dravid. On subcontinental pitches, players who are less technically solid than him bring more value because they are flashier than him and can get the tempo going. To be honest, Shikhar has not done badly in the past few games. A hundred, a 50 and a pretty good knock (by T20 standards) today makes him prime contender to stay in the team. And on Indian pitches with his left hand variety, he is an easy pick over Rahane. Dhoni has been recently talking about this "different players for different formats". Nothing wrong in Rahane focusing on tests and playing the occaional ODI's and T20's for India when we tour overseas.
If you seriously think Rahane is anther Dravid then you clearly haven't seen Rahane play much. He has the ability to score runs quickly. However, he needs to bat at a position which is best suited for him in limited overs format which is opening. He has the ability to anchor the inning and can also go after the bowling. Again, he won't go after the bowling like Dhawan does but he will provide better start more consistently than Dhawan. Dhawan can win matches on his day but I haven't seen him do that in any T20 matches. Not even at IPL or International T20.