Board Thread:Questions and Answers/@comment-6088207-20130124020332/@comment-4800978-20130124023520

1) Because why not?

2) Because Yamamoto ordered her not to. She was greatly conflicted about this, as you'd of noticed if you'd followed it closely.

3) Because the survivor will be many times stronger and a greater asset them just two captains of low level.

4) Because strength isn't the sole factor the decides a leader. Unohana has a history of being a diabolical criminal and her friendly persona appears to be just a facade. Kyoraku is capable of leading a group, and has already proven this. He is strong, level-headed and makes the right decisions, even if Central 46 disagrees.