I have been doing some thinking about the actual unlock quest chain, and while I do like uniting different clans, realistically it would be less work to just say that the Stonemaul clan represents the playable Ogre faction. As Syegfryed mentioned, theres different skin tones from the Stonemaul in Dustwallow Marsh, and since Void Elves are a thing, the huge influx of traveling Stonemaul Ogres doesn’t really need to be explained much in detail.
Thus, if we’re dealing with just the Stonemaul Ogres being recruited, maybe the Dunemaul are being used for the benefit of Megs as opposed to the Horde and the Draenor Ogres could have just joined the Stonemaul clan, heres an idea I had involving just recruiting the Stonemaul clan.
For simplicity’s sake, lets assume that Sylvanas is still Warchief, and that if a dethrone attempt occurs, it comes afterwards.
Interestingly enough, one of the first quests you can get in Dustwallow comes from an Ogre, I’ll mention him later, who mentions their wife having been killed fleeing their original home, so the clan does have women. Either a female Ogre model can be made and inserted in the area without mention, or we can just say that a clan of Ogre women, from that amazon island mentioned earlier, have arrived for reasons and decide to join and mate with the Stonemaul clan.
Also since the Stonemaul did arrive in Kalimdor from Lorderon via ships, they should know ship building and the knowledge of being shipwrights. Thus, if we’re tying them into a BfA allied race, and Dustwallow is right next to the sea and Theramore is gone, it gives them a good reason to join a sea-themed expansion and give another port area for the Horde.
So who would be the one to offer the allied race unlock quest after requirements are met? Rexxar is the obvious choice, having ties with the clan and the clan itself already part of the Horde. Rexxar can cite these ties to Sylvanas, mention they know how to make ships, and they would be a huge asset as reinforcements in Dustwallow and Feralas.
Two themes come to mind with the Stonemaul specifically: Reclaim their home and Dire Maul. Lets start with the former.
Your character and Rexxar arrive in Dustwallow and find that theres trouble brewing with the remaining black dragonflight mobs that are there. The new leader from the Cataclysm questline in Dustwallow Marsh is Tharg, the one whose wife died I mentioned and who became chieftain after you ran off the last one, and asks you for help. Suddenly, the blackdragon flight just outright raid the Ogre town you’re in, which you help fend off.
Tharg decides enough is enough, and pleads to Rexxar once more to lead an attack on the rest of the dragonflight and help reclaim their village lands that he misses and wants back. Thus, you, Rexxar, some Horde members, and the Stonemaul launch a counter attack. If we want to tie this into BfA, lets say that the naga involved in 8.2 struck a deal with the black dragonflight offscreen to hassle the Horde to keep them busy, with a named naga as the leader that needs to be defeated. If not that, then someone that isn’t a black dragonflight member could be trying to assist them to harass the Horde for reasons. This ends with the reclamation of the Stonemaul ruins so they can start rebuilding.
At this point, I’d like to credit Keeper of Lore, from the video I linked earlier, for inspiration for the following:
At this point, the Stonemaul are indebted to the Horde, so we get a progress report on their operation in Feralas regarding Dire Maul. A plan of attack has been made in order to take the former High Elf city for the Horde. Thus, we fly to their base and see a few different armies there. We have the Stonemaul Ogres, Blood Elves, who want to help reclaim it and study its magical properties, and Nightborne who are interested in its magical properties. If San’layn are part of the Horde, have them there also for the same reasons. If Vulpera are part of the Horde, have them there to help scavenge and treasure hunt with the other races.
Thus, we do an attack on Dire Maul against the beings that are there. The Gordunni and other inhabitants fight back to keep their territory, but ultimately the Horde succeeds…until the Alliance attack.
Now, Keeper of Lore brought up the idea of Feralas as a warfront and an introduction to the Night Elf Worgen, so if they were an allied race for the Alliance, they would appear here with other Alliance races, and likely their unlock questline would lead them here on the Alliance side. If not, then an army of Night Elves, regular Worgen, Void Elves, and a few High Elves would be attacking, thinking the Horde would be weak from the previous battle. Same army, just without Night Elf Worgen.
If a warfront is planned, it could lead to a stalemate and a retreat on both sides. If not, then the Horde would win the battle, but have to defend it against the Alliance who likely would be launching regular attacks on it.
Regardless of circumstances, and preferably with that Ogre victory party I mentioned before, Rexxar would call on the Stonemaul Clan’s debt to help the Horde either in whatever the current expansion is, help build ships for the Horde, or to help them in Feralas as a warfront if that is a possibility, along with a reinforced Horde presence in Dustwallow Marsh.
Thus, you return to the embassy, and much to the chagrin of Nathanos, Tharg appears and gets officially inducted into the Horde from Rexxar. We could even get a scene between Rexxar and Tharg, hinting that the Stonemaul may pay their debt back if they are needed in the near future, hinting at a possibility of the Horde overthrowing Sylvanas if that is the direction the plot is heading.
In this case, we have something a bit more serious, could fit in the lore, have an alliance counterpart, and opens up some possibilities depending on what direction the devs want to head in story-wise. The Ogre contests I mentioned could just be their own thing that is for fun in Dustwallow, not tied into anything. Also, I still think the Goblins using their tech for you to control a giant Ogre against the Alliance army can still work here.
This questline isn’t perfect, and I’m sure things can be debatable, but hey, at least it is something.