Originally Posted by
Wildberry
I would start by rejecting the premise that Allied Races necessarily need to have an arbitrary correlation with their "Parent Race." I think between Kul Tiran using an entirely custom rig, & Vulpera having no real link to Goblins, there's enough precedent for standalone Allied Races that don't need to be "The Worgen Allied Race™," for example.
With that in mind, here are a few that I feel would be inherently better than any Shadowlands denizen simply on account of the fact that they're more well-established in lore, have (semi-)plausible reasons to join a faction, are mortal & consequently tied to Azeroth, and don't have their racial existence undermined by interfering in mortal affairs.
Alliance:
-Broken Draenei
-Furbolg
-Jinyu
-Frostborn Dwarves
-Iron Dwarves
-Arrakoa
Either:
-Vrykul
-Naga
-Ethereal
-Tortollan
-Tuskarr
Horde:
-Ogre
-Mok'nathal
-Taunka
-Hozen
-Gilgoblin
-Forest Troll
-San'layn
etc.
Overall, there are only three on that list that I'm personally dying to play, and I'm largely uninterested in the rest. But just off the top of my head, we can justify all of those (Though some may be mutually exclusive [Dwarf variants]) according to current Allied Race Precedents.