Im fine with the controls as it is but I found it quite easy to exploit the defense spell The Royal Archaist has by spamming it when the opponent using its most powerful move in story mode then spamming the basic attack which allows you to rack up damage fairly quickly. I don't know if debuffs damage are lowered in higher difficulty seeing I only beaten easy mode but you could take it into consideration.
I'm guessing your going to lower the difficulty anyway but if your going to make an insane mode or just increase the difficulty of hard mode you should lower the damage the debuffs do.
But that's just my opinion