I know what you are saying, and it would seem like wisdom, but for the warning in my heart. It's just too convenient. It's true Kenpachi cares for nothing but fighting, but his and Yachiru's history gives you the impression Zaraki is a real killer, not just some sporty matching man. And he's always talking about fights to the death and killing the opponent. I'd think he's kind of happy if some really strong opponents barely survive, but someone like Ichinose? I don't think he would ever be any real opponent for Kenpachi, not in a thousand years.