My #1 is Alliance Gnolls. Followed by Horde Forest Trolls.
Even when the game first launched you saw all these mixed-race factions such as the Southsea Pirates, Venture Mining Company, and the slaves of the Dark Iron Dwarves. They all contained the player races but also, in addition, Goblins, High Elves, Ogres and Gnolls.
Now, of those-- Goblins and High Elves did make it into the game. And we know that the Horde should get Ogres and Forest Trolls since the Stonemaul Ogres and Revantusk Trolls used to be factions even before The Burning Crusade launched.
That leaves the Gnolls as the weird ones out. So many quests that involve them have the other races treating them like animals and “culling” them even though we know that they are intelligent, sentient people who are perfectly capable of working alongside other races-- more so than Quilboar, Kobolds, Harpies, and even Furbolgs. Gnolls were uniquely framed as a race perfectly capable of being a cooperative and productive members of mixed-race factions. And since Goblins and Ogres seemed Horde aligned, it just made sense that High Elves and Gnolls would be future Alliance races.
Instead the Alliance got Werewolves and Demons? Even Pandas and Dragonpeople were added first?
The idea of the Gnolls getting a charismatic leader who is willing to work with the Alliance rather than against them isn’t a wild idea-- a lot of those bad Gnolls are working for humans or goblins anyway. So them getting a leader who realizes that continuing a losing battle makes no sense and they could lead better lives if they work as mercenaries for their oppressors rather than trying fruitlessly to overthrow them.
And it would show that the Alliance has developed in character overtime by trying to uplift them rather than continuing to stomp down on them. Particularly now that troops are becoming ever more scarce.
And it would finally add a proper scrappy underdog race to the Alliance which they have been sorely missing.
The Gnoll models seem to be based on the Worgen model which means a proper dedicated female Gnoll model that uses the skeleton and proportion of the female Worgen would also work just fine. They could then use all of the Worgen armor models. They would work ideally as the sort of “Allied Race” we have had since the idea launched where they reflect a race that already exists-- but in this case it would be something that’s been part of the setting for 25 years instead of something someone came up with only within the latest expansion.
It wouldn’t even have to be all that wild departure. Other than the charismatic leader, the general attitude we see could still be that the other races in the Alliance don’t totally trust or regard the Gnolls very highly aside from your particular character who has a long distinguished record. They could often take on the roles of the hapless, unlucky, or foolish stock soldiers that bad things happen to.
They would also definitely be able to be Shaman which would add another race that can use that class to the Alliance.