Allied races are supposed to be like skins for preexisting races.
Let’s go over the motivation/justification (as I understand it) for each allied race:
- Lightforged Draenei - More militant-minded Draenei. Less willing to compromise in pursuit of their goals.
- Highmountain Tauren - More fierce/warlike/tough than Thunder Bluff Tauren.
- Void Elves - Blood elves for the Alliance. Gives the Alliance more dark-themed magic.
- Nightborne - Night elves for the Horde. Gives the Horde more arcane-themed magic.
- Dark Iron Dwarves - “Evil” dwarf race for the Alliance.
- Mag’har Orcs - An uncorrupted orc race for the Horde. More pure/primal.
- Kul Tiran Humans - Big/tough human race for the Alliance.
- Zandalari Trolls - Male trolls who can walk upright. More civilized race for the Horde that doesn’t have Alliance origins (looking at you, Blood Elves and Forsaken) and has human-like proportions (looking at you, Goblins).
And now we come to the most recent and controversial Allied races. The infamous Mechagnomes and beloved Vulpera. At least those are the popular sentiments that I have heard from the most outspoken people.
Mechagnomes. Their motivation/justification is that they are a more combat-effective gnome who are willing and eager to use their technology in battle in a serious, non-comic relief kind of way. They are kind of like Lightforged Draenei in that they have a different attitude towards battle/war then the race they are based on.
Vulpera. As I’m sure you noticed, all the previous races (including Mechagnomes) were based on a pre-existing race. They are essentially versions of races we already had, just with their physical features and culture tweaked a bit. Vulpera break from this pattern.
They are probably supposed to be based on Goblins. However, the only thing they share with Goblins is their skeleton. Their physical features and culture are otherwise completely different. This is where I believe the accusations of unfairness by the Alliance are coming from.
Even if Mechagnomes were perceived as a “cool” and desirable race (and some people do perceive them that way), they would still be just a gnome variant. Vulpera, however, even if the majority of people hated them, would at least have the saving grace of being a completely unique race (within the Warcraft universe).
Blizzard gave the Horde what feels like a completely new race, while giving the Alliance the standard Allied race (variant of an existing race). It doesn’t help that Gnomes are an historically unpopular race, while people love the idea of small, cute, playable foxes.
If the Horde had gotten Gilgoblins (which are based on actual goblins) instead (I heard this suggested in another thread), there would have been parity between factions, and likely less complaining (I mean, gnomes would still have been unpopular, but what can you do? There had to be a gnome variant eventually or gnome players would have felt left out. And it might as well be now.) Their motivation/justification would have been that they are more physical combat minded versions of goblins (who actually look like goblins), similar to the justification for Mechagnomes.
)