http://www.espncricinfo.com/story/_...-assurance-consistency-middle-order-aspirants
This interview of Rohit Sharma (post Asia Cup win) further confirms why he should be India's full time captain, ahead of Virat Kohli. Especially this paragraph -
When we came here, I wanted to give them the assurance first that they will play all the games. That's how you make players. You give them the assurance of going and playing freely without taking pressure. If you know that you're going to be dropped after two games, it's not easy for anyone. I think it is important to keep that team consistently going, and that is something that we spoke at the start of the tournament. I wanted to give everybody a fair run and play more games. That's how you will understand a player's capability because in one-odd game you can't judge. You need quite a few games."
You can just see the thought process here. Rayudu and Karthik were given a good run in this tournament and batted well for the team. They might not have gotten huge runs, but considering that the pitches this tournament were mostly very tricky, they batted for the situation and helped the team win. Also for that dead rubber game, Rohit just went full monty and dropped almost all the frontline players, including himself, so that the bench gets the much needed game time. I'm pretty confident that if Kohli was captain, he would've said "oh we need to treat every game as a must-win and so we should not be dropping too many players".
Kohli is still a great batsman (TBH, I am proud of his batting and the way he overcame the England conditions to have a fantastic series) but I seriously think India would be best served to have Rohit as full time captain and Kohli as the premier batsman. In tests, it should be Rahane with Pujara or Ashwin as vice captain.