I don't think the evoker has any identity. It's the boring subclass for casual players like the life cleric and the champion.We know that straight Evoker is one of the four from UA5. So they're likely going for the ones with strongest themes and identity, not trying to fit in all eight schools. My money is on Evoker, Illusionist, Necromancer, and the fourth will be a wildcard that isn't a school based subclass at all. Either Bladesinger if they're willing to put the melee cantrips in the PHB or a brand new subclass if they're not.
DM: What kind of wizard do you want to be?
Player: I dunno, someone who blasts things?