User blog comment:Xilinoc/Ch. -547 - The State of Affairs op. 1 - "Expectations"/@comment-11163184-20130724184619/@comment-11051098-20130729114252

Yamamoto did live for more than 2100 years. He could simply have been too stuck in the past, how things were when he was young and the mentalities he grew up with and learned.

Shunsui is definitely the man who can change the things Yamamoto didn't want to change. He doesn't refrain from using all the help he can get when it's needed, be it from Arrancars, humans etc.