- you could create 4 such schools:
1) primal magic
2) magic of darkness and light
3) magic of ice and flame
4) magic of wind and earth
that is, we get 7 distinct schools of magic, studied according to the principle of opposites. For example, "bestower of protection" and "lord of pain" clearly belong to the "magic of wind and earth," teleport and elemental summoning spells belong to primal magic, etc. - I haven't fully thought this through yet, and it seems quite unusual to me, but maybe someone will like it or it will become a basis for other ideas. So, here's an idea.
Блистает там воздушностью прогалин.
Но между кедров, полных тишиной,
Расщелина по склону ниспадала.
О, никогда под бледною луной
Так пышен не был тот уют лесной...