Larkin is the only choice, and this hand-wringing over future captain possibilities conflicting with Larkin wearing the C are.... silly. Something, something, bridge, something, when we get to it. Larkin would really have to fall off for anyone currently within the organization to be a clear-cut better choice. And that's not something you bet on happening as an organization unless you want to risk spinning your wheels for eternity.
No one here knows exactly why there was a delay in naming the next captain. Maybe they wanted Larkin to develop further in that way. Maybe they didn't want such a huge burden on someone as young as him while the team was still spiraling downward and ultimately bottoming out last season. Maybe some combo. Maybe something else. But this suggestion from HSJ and others that they should continue to wait is wrong. This team will still be bad, yes, but they are finally on the upswing. They will be better than last year. Next year they should be better than this year. And you want a named captain at the helm during the ascent. Accountability is about to become even more important, and Larkin has shown to be probably the most accountable player on the team (he is that way partly because this is already, and has been, his team.... just without the C). He's ready to be the one to hold others to account.
Also, his dip in point production for the first half of last season doesn't matter. It's a blip. Immaterial. His conduct on the ice has very much improved over the past several seasons, and his poise in public-facing situations is appropriate. And as others have said, the kid is a worker, he brings it all the time.
I like Bert a lot, and DDK is a fine enough player, but neither are "C" material. They are both complementary players and don't really have strong personalities. Hell, Bert stares at the ground 80% of the time during interviews. And DDK has major health concerns, which is unfortunately for him a factor.