That's dumb. You invested in the spell schools but not in enchanting? Enchanting is the most powerful perk tree in the game. If you get enchanting up to 100 and get all the perks (except the soul siphon branch - useless), you can enchant armor, rings and amulets to 25% spell school cost reduction. Get 4 items like that and you can cast ANY spells from a single school entirely for free. Plus you get an extra effect per armor and 2 more armor pieces (2 effects each) to play with. You can easily get close to 100% damage reduction for a type of damage like frost. That's right, enchant some armor to 25% reduction in destruction and you can cast fully charged fireballs for free. Completely. Your magicka bar won't even show up when you use the spell. That means you can be a shield + sword warrior with all related fighting perks by level 60 (this includes the smithing perks needed for Daedric smithing) that can cast fireball for free. Yeah, the magic school perks don't seem so useful now, do they? The main perks there just give you cost reduction to spell schools, but who cares about that when you can cast the spells for free?