This is the worst idea they had so far. I don't understand this choice at all.
What if i do not want to get hate and instead of casting Fire IV, cast Fire III?
It is essential for any casting class to be able to choose the spell potency and not go METEOOOOOOOOOOOR! every cast creating so much hate you die every time you cast it.
I am baffled, i don't know what they are thinking this will do to improve the gameplay.
Please re-consider this SE, it's does not make sense unless you give us a way to influence the potency of the spell.