User blog comment:DazzlingEmerald/Not Another One! Fanon Canon: Plot "Z" (Soul Society Civil War)/@comment-18812574-20150412044823/@comment-18812574-20150412131907

I agree with N. They've had nine years to sit and stew over what happened with the Quincy, and until now nothing really major has seemed to, well, happen. Furthermore, the Gotei 13 is currently filled with a bunch of new faces, with little or no connection or even awareness of who Raien is. It wouldn't be impossible for his appearance to incite a rebellion within the Gotei 13, but at this point I'm not sure how realistic it would be.

Also, I asked this before but, what, exactly, is he defecting from? Soul Society is a place, not an organization last time I checked.