At least they could have been made as a single subclass called Specialist or whatevs; the features those subclasses gains are so minor that just having generic boost to spells of particular schools would be probably as desirable.
2: Pick a school: 50% less time/cash to copy spells AND craft scrolls or magic items replicating spells from that schools.
Pick to spells from your school for each level, they are always prepared and dont count against your max prepared spells.
6: +1 Spell DC/ Spell attack with your chosen school's spells. +1 again at lvl 14. Your allies have advantage on saves against your spells from your school.
10: Advantage on saves & skill checks against your school. Resistance to the damage dealt by spells of your school.
14: Concentration on spells from you school cant be broken. When you cast a spell from your school of 2nd level or higher using a spell slot, you regain one expended spell slot. The slot you regain must be of a level lower than the spell you cast and can't be higher than 3rd level.