I am having the suspicion that the Kaiten removal might be more motivated by high ability input, rather than button bloat. Kaiten comes up quite often in the rotation, more so than shoha, ogi or even tsubame.
True, unifying those actions and their follow up actions, into morphing keys, would help actual button bloat.
However, I expect Kaiten was chosen for removal, to lower the cpm between various different key inputs instead. Kaiten is a good candidate for this result, as it is used so frequently.