Got your math wrong there. With Shadowbringers we will have 4 tanks/3 healers/4 melee/3 physical ranged/and 3 magic ranged (4 if you count BLU, but I'm not going to get into counting limited classes because thats not fair). I do expect that by next expansion we will see a new healer, because that much neglect to an entire 1/3 of the Holy Trinity is a problem