I think a few simultaneous attacks would be acceptable in Bankai. I like what you have now, though. It exudes a sense of control and manipulation which we know is a large part of who Osamu is. ;P

As it is now, it's very adaptable and sleightful, which I appreciate for originality's sake.

Also, Akimoto does not continue to regenerate, it is a one-time occurance. He's just more robust afterward. ;)
But I like that you took into account other CS's to gauge your own. Good idea. ^^