I’d say their customisation options go well beyond that.
You have the Blackrock skin (dark grey with rock-like designs across their shoulders and bright yellow eyes), Laughing Skull and Burning Blade (grey with piercings and scars), Bleeding Hollow and Thunderlord (red-brown with or without white markings and war paint), and finally Frostwolf and Warsong (plain brown with or without black Garrosh-like tattoos).
The combinations were recently adjusted so as to enable more freedom in customisation, but in all, it’s very easy to identify distinct clans depending on the skin used. Specially given there are even lore reasons for some of them.
After getting more immersed in other mediums that handle these differences in their own way, I do not see the problem to be honest.
Going back to the D&D angle, on top of cultural differences, these humans were also portrayed with physical differences. In fact, I can’t currently think of a single fantasy setting dealing with distinct human groups, that didn’t mark distinctions amongst them. Even if they ultimately converged and cohabitated in the same place.
Being that place Neverwinter in D&D, Kings Landing in ASoIaF, Altdorf in Warhammer, Minas Tirith in LotR, etc.
Why would WoW be any different? I just do not understand what makes it particularly problematic here.
Centuries of mixing in Stormwind would even cause these differences to be but a hardly relevant footnote, as most features would’ve already been spread as soon as the population mingled together and new generations with parents of different heritage, grew.
You think people would feel unwelcome if the setting elaborated more on background development for the notably obvious physical differences humans have?
Are we to accept that humans in WoW, and in WoW alone, are to be tied to meta limitations regarding the treatment of their nations?
Why is it that no other setting is limited in said way?
We want depth for them, and yet we put up these limitations.
Wouldn’t it make more sense to develop fantasy separately from reality?
To be honest, I doubt a lot of people want a self-insert in the game.
I can identify myself with the values of a non-human race. Or maybe I just want to play as something that feels completely alien.
In all, and even if as I said the physical bit isn’t really my focus here, I do believe that it would be a good leg to lean on while developing the overall lore of the race.
I’ll repeat, that other mediums used it so, with undeniably good results.
In fact, other WoW races do so to this day.
But again, I repeat that this isn’t really that relevant to me. As I mentioned to Baalsamael, even if these humans started having distinct features depending on their kingdom, after generations of coexistence, at this point humanity’s population would all be of mixed heritage.