To be honest, I prefer that the Allied race system is used to create whole new races like say the Vulpera then use the system that could have been or should be customization options.
Allied races now came out before they thought about Customizations, as the system started in late legion, and then continued on in BFA as a focal point of the expansion story. Breaking down those races we got, many should have been straight up customizations over actual races.
Alliance:
With the alliance, only Dark iron, Kul Tirans and Void Elves made sense to be races with the Lightforge and Mechagnomes should have been customizations.
Horde:
Nightborn, the Zandalari and the Vulpera as well made sense with the Vulpera being based off no other race in the game (they may use the goblin rigging for movement, but they aren’t anywhere close to looking like a goblin)
The Highmountain and the Orc’s from the AU WoD should have been customizations.
The Man’ari fall into a customization category as its better to add a few skin tones and eye customizations to a race rather than trying to use the assets to try and turn it into a race and calling it a “allied race”.
I would rather Blizzard go the route of what they did with the Vulpera when it comes in making “Allied” races then using the same model that we have right now and slapping on different colors and then calling it a “Allied” race.