<Snipped quote by Light>
... What does everyone think?
If I may, I'd like to suggest a bit of a simplification to the system, mostly just a condensing of schools into categories that capture more under one umbrella, so people can pick more freely and still play into niche power fantasies. The core idea is the same- give people the ability to pick schools and still have the freedom to express how their character uses that school, potentially differently from others. I just believe that with less schools, we can achieve that "unique expression" even more, and have less edge cases of "I want to use a certain kind of magic but there isn't a school that really captures/allows it."
There are 7 schools/attunements/affinities this way: Air, Cosmic, Earth, Fire, Occult, Radiant and Water.
Air, Earth, Fire and Water would be the central schools, focusing on manipulation of the world around us. Air would take on the responsibilities of electromancy. Earth would be the unions of geomancy, metallurgy and the magic of nature's plant and animal life. Fire is mostly unchanged, as it's a well-established archetype that needs little more than heat, flames, embers and smoke. Water would inherit cryomancy as well.
The remaining three schools of Cosmic, Occult and Radiant would take on the job of more esoteric magics, with perhaps Radiant still being allowed as a non-forbidden school.
Occult represents most of what you'd consider forbidden magic. Hellish or eldtritch rituals, illusions and mental manipulations, and of course all forms of dark life-exchanging magic such as sangromancy/hemeomancy, osteomancy and fully fledged necromancy.
Cosmic would be a fringe case on how/if its use is allowed. As likely the least undstood school, Cosmic reaches deepest into the void to control space and time with telekinesis, chronomancy, and teleportation. Cosmic would also be responsible for "null type" magics such as force, kinetics and sound.
Radiant is the closest one could analog to divine magic. Still a scholarly and learned art, it would encompass light (both illumination and hard-light objects), order, and most other magics you could associate with prototypical clerics and paladins from other fantasy settings.
I want to point out that I did not attribute healing to any of the schools here, any school should be able to interpret their magic in a way that allows them to heal in some way.
Edit: my phone can't spell Cosmic apparently, and thought I was still talking about Occult.