In the last match, a lot of people did question that a little. Because after all 215 is not a small target to chase. But even after that CSK did really well to get to the reduced target which was given through the Duckworth-Lewis method. On paper, CSK had no chance. But they overcame all the obstacles.
Questioning Dhoni's captaincy? Lol. I have no idea who those people are, but they are seriously dumb as hell to question his captaincy after all his achievements so far. He is the greatest legend in the history of cricket in my opinion.
Also, writing off CSK just because the target was 200+ is downright silly. This is the IPL where miracles happen on a regular basis.