I feel like her expressions makes her spells seem weaker, like it isn't that big of a deal at all. It can work if you had contrasted it with a big ominous monster, so she seems like a badass beating monsters effortlessly.
But just this makes it seem like magic is an everyday task that she is bored with. Imagine she finishes that spell and all it does is do the laundry of her entire magic school, that's what I get from the expression. She on her own doesn't carry enough weight in order to make the art impactfull you should have added more elements in order for the art to be complete.
I saw how you said that it was rushed, and I get it, but next time I think it would be better if you didn't put all your eggs in one basket and designed more elements around her, so they can complement each other. I know it sounds like I hate the art, but there are a lot of great elements, like her posture, clothing and the way the spell looks.