The problem with that analysis is that, in WoW, ideology and racial aesthetics are inextricably linked.
Ok, so you’re proposing a faction conflict where the factions were more defined by their ideologies rather than the races that participate in their composition. So I suppose the best example of this kind of model would be found in the Elder Scrolls Online, where any race from the 10 playable races can elect to be in any of the three available factions.
The problem arises if I were to ask you to describe or at least envision the aesthetic of the playable factions. It’s a lot harder to do because ideology is not necessarily tangible. It’s important, sure, but in a video game where being “iconic” is oftentimes coveted, it isn’t worth sacrificing aesthetics for ideology.
Which is why WoW lore is constructed so that, for the most part, the races actually embody the ideologies of their factions. You can literally see the Horde’s ideology in the physicality of orcs, for instance. It is why, for years now, the term Horde has had an immediate connotation with the image of an orc, even for those that have never played WoW. It is as strong a word association as Disney and Mickey, Batman and DC, etc. I struggle to consider an eventuality where the Alliance receives some manner of reskinned orc as an allied race. To see orcs running about Stormwind would be jarring, and there’s a visual cost to something like that.
That’s also not taking into consideration the fact that developing reskins and shuffling them off to the other faction runs the risk of being wildly two-dimensional. I’ve seen requests for Lightforged Undead for the Alliance and Eredar for the Horde. That’s essentially just asking for a palette swap to emphasize one race’s “goodness” and another race’s “evilness” and situate them within factions that are only deemed “good” and “evil” due to in-lore stereotypes. If Blizzard truly wanted to emphasize Azeroth as a world with “shades of grey,” then the absolute worst thing they could do is create Lightforged Undead or Eredar and give them to the opposite faction.