Kohli would find it really hard captaining a side with the three hallowed dinos still in it. Let him mature a little first, and even then I don't think he'll possess the gravitas to captain an international sporting side. Bluster alone doesn't cut it.
Sehwag is a village bumpkin, and I intend that to be an insult.
I never thought Ganguly was a particularly imaginative captain vis a vis field settings either. Dhoni, I felt, had something about him - for instance, that time he completely choked off scoring outside the off in India against Aus; it revealed a hard as nails side to him. During whatever fleeting successes we had, he always seemed to make the right bowling changes at the right times. I was, and still am a fan of his assured presence, but he seems to have fallen away recently. Maybe there is some substance to rumors of dissent within the ranks.
Look, I know this is flogging a dead horse, but until the old guys bugger off, new positions won't open up, and we are not going to be in any position to judge the captaincy credentials of our new crop. IMO, the only way forward is to give the job to a fresh faced kid, but at the moment it's a little difficult to pin down just who that might be. Best bet would be persist with Dhoni till the oldies go away. We're not playing away cricket for two years anyway, so I imagine he'll score a few runs on the SC as well. In about two years, we should have a clearer picture emerging.