Dragonflight is already going to bring us Rogue, Mage, and Priest to all the races that don’t currently have it. I believe everybody can also already be Warrior and Hunter.
As for the rest of them, I don’t personally want to just abandon the lore surrounding some of them even if the game hasn’t treated lore terribly well recently. Based on what we know, things like void elf paladins should be impossible without them simply just exploding.
What I’d want to see is a bunch of class reskins added. They don’t change any mechanics, but the names and spell effects are changed to give it a new thematic.
Then they could have skins be limited by race to give racial identity, and we could have things like a void elf “void knight” or something that is mechanically a paladin but doesn’t have the lore issue with void + light.