Most classes i think it would be fine. There are outliers or "special cases":
1. Druids: Leave them as it is, adding the Kul-tirans to it was a bit of a stretch, but since Horde were getting Zandalari Druids, it kinda had to be done for balancing reasons. (I kinda would have liked to see mecha-gnome druids instead of kul-tirans, but it would have to be a complete new lore, so they'd all be mechanical based, etc. Probably too much effort for blizzard to add for a single Allied Race)
2. Shamans: I wouldn't add any. Connection to the elements is required, a Undead Shaman would make zero sense for example.
3. DH's: i could live with Nightborne and Void Elves being included here. Void elves are a bit more of a stretch i know, but they could fit in. Nothing else.
4. Warlock: Probably contentious, but i'm not sure that mecha-gnomes AND vulpera make sense here. Specially mecha-gnomes, but if they added it, it will never get removed now.