So you're not against having an attribute that increases spell power, you just want it named the way you want. That's just quibbling.
Willpower is not a primary attribute, Larian thought about making it one, but decided against it. Willpower has a purpose in the game to help you cast defensively. The point that you're missing is that Intelligence could use something to make it a bit more useful. Maybe increasing spell power is what it should do, maybe it should do something else.
