EzekielRaiden
Follower of the Way
Evocation and Abjuration would have tradition-focused fans, I suspect, since they represent some of the most "classically D&D-Wizard" spells. Divination is in kind of a weird spot, because prior to 5e it was extremely weak as a school, but now it's arguably the best of the bunch because of Portent (probably the only truly powerful Wizard subclass feature.)I'm usually one for thinking familiarity and tradition aren't awful reasons for keeping something (as long as it doesn't hurt others!). But is there any reason to keep these particular eight schools besides tradition, and are there any folks who are super-fans of the current division who would be upset if they were merged a bit? I can imagine illusionist having historical momentum, any others?
Conjuration and Transmutation might have fans because they were brokenly OP in 3e, and thus people might want to hold onto them.
Necromancy and Enchantment...harder to say. There's certainly room to argue that Illusion and Enchantment could just be folded into a single school, and that Necromancy could be classified as a subset of Transmutation since...I mean it literally is about transmuting (formerly-)living things into undead things.
If I were combining based on common themes, I would combine Illusion and Enchantment into a single school (probably still called "Enchantment" but "Glamour" could work), and probably just fully merge Necromancy in as a subset of Transmutation. From there, it's just a matter of looking for things that seem reasonable among the remainder. Combining Evocation and Abjuration into a single school seems pretty reasonable, and would make for probably the single most obviously "D&D Wizard" subclass you could get what with having fireball, mage armor, counterspell, magic missile, and a host of other quintessentially D&D spells in there.
So that would have Enchantment (absorbing Illusion), Transmutation (absorbing Necromancy), Evocation (absorbing Abjuration), Conjuration, and Divination. And those last two do have a kind of unexpected connection, since Conjuration relates to teleportation and thus depends on knowledge, and Divination depends on going to places (usually with magical sensors or remote viewing) and such. Probably have Conjuration absorb Divination.