Hitsugaya is just a child, and several people have commented that his bankai is not strong enough yet to really stand against other bankais. He is progressing at a fast rate, but he's not there yet.Because the once-thought-unstoppable shinigami Yamato was defeated and killed by Juha Bach, the central 46/Gotei 12 convened and deemed Shunsui Kyoraku as the new Captain-Commander. While he is indeed one of my favorite captains in Soul Society, the thought of his Commandership seems a little hasty and odd. What happened to Ukitake or Toshirou? These two seemed more apt to handling the responsibilities better than someone of a laid-back nature.
This is different than, say, the Narutoverse, because the Hokage has a Jonin Commander to help advise decisions.
The Captain Commander decides all.
So there's my thoughts. Who do you think would make the best Captain-Commander? All 12 Captains, including Yoruichi and Ikkaku, apply. I may or may not post a poll later.
Ukitake is described several times as being sickly and is often ill. He does have the better personality for the job, however.
Shunsui is too laid back and lazy for the position, and his zanpakuto is a stupid one. If he's the last line of defense, the gotei 13 can't really rely on him being able to use his zanpakuto (it isn't always in the mood to "play" and the rules of it affect him the same as the enemies, which can create problems).
I hate to say this, because I really don't like Byakuya, but he would probably be the best choice. He's powerful, he's strict and fair, he has abnormally high respect for rules and chain-of-command, he's from a noble family, he's probably the best kido user of all the captains, and he would be good with the various parts of the job. He's arrogant and not particularly respectful to people under him, but he's definitely better than Shunsui.