I have created a forum account just to feedback publically about this.

Samurai does have button bloat, that in undeniable, and while it's manageable for most right now, it'll get worse later. So efforts to fix that are welcome. But Kaiten is the wrong skill to target to reduce this.

This isn't because Kaiten use is skillful – it's not – and I assume that the numbers will all make sense down the road, but rather because the loop of that flourish of the sword before delivering the key attacks that the entire class is built around just feels good. This is both because the animations work so incredibly well together, in a way that hasn't been topped yet, and also from a purely human perspective: you're taking this short breath before delivering the big hit you've built up to.

In short, while I understand that Kaiten doesn't add much from a purely game system point of view, it is central to the feeling of the class, and will be missed.