it must be that Kubo isnt getting paid enough, so he is making every instance of his manga lamer than it potentially should be. Or the guy simply runs out of creativity (which i dont have, but i know a good piece of work when i see it.)
There is really no point in such a bankai when you are fighting headon with a shinigami. For killing lots of hollows, sure! It's rather like a gun really, maybe even better. But its use is limitted. Maybe a couple more chapters, then Ill call it quit.