Ageha is not essential to the rotation, all you do is press it when the enemy is at <20%, better remove it.
Seigan is not essential to the rotation, all you do is press it after mitigating an attack, better remove it.
Kaiten is not essential to the rotation, all you do is press it before Iaijutsu, better remove it.
Meditate is not essential to the rotation, all you do is press it when you can't hit the boss, better remove it.
Hakaze is not essential to the rotation, all you do is press it before Jinpu, Shifu, and Yukikaze, better remove it.
Etc.

A line has to be drawn somewhere. Shallow justifications can be used to remove any skill in the game, that does not mean it is a good idea or that players should accept it.