Board Thread:Improvements and Issues/@comment-33728110-20200803202155/@comment-5398287-20200804181859

It actually IS implied that she can't in the previous chapter, when she strikes Kenpachi and he just bounces back to attack her rather than go down - the implication is that he's at a new level of power where just her Zanpakutō won't cut it anymore for this specific purpose. And if her Bankai had the specific power of reviving whoever it cuts down, why wouldn't she just have used it from the beginning? The far more likely explanation is that it has crazy offensive power and Kenpachi just needed to be at a high enough level of power to withstand it even a bit so Unohana could keep healing them.

You can disagree with the power listed by the wiki all you want, but nothing you've listed here is convincing enough to change it to anything else or supported enough by the facts of the manga, unlike the acid power that I discussed first with Salubri (who knows his stuff about this series more than anyone else I've ever met), so it's staying as-is.