User blog comment:Theformerprez/The Weakest & Most Useless Bankai's In Bleach/@comment-29359011-20161115114541/@comment-24769684-20161115120212

Yoruichi said that it usually takes 10 years for a Shinigami to achieve Bankai. So I can understand the complaints about some of the more recent ones especially Kenpachi's which was absolutely garbage (though power wise it was pretty great)