The other has been straightforward bigotry.
It's fair to say that Games Workshop has not had a great record on representation over the years and has been more than willing to follow this "white and male is the default" line. Female characters have existed, but they have tended to be restricted to specific units or armies, often with suspiciously little clothing.
As far as non-white characters go, Games Workshop has, if anything, been even worse. The Warhammer World was set up as an analogue to our own world in which the most of it outside of Europe was either unexplored, uninhabited or full of monsters. Gav Thorpe, rightly, pointed out that there are a quadrillion humans in the Imperium, but its funny how most of those painted by the design studio have ended up as white.
This is something that Games Workshop have been trying to address, albeit slowly. A handful of non-white characters have crept into Age of Sigmar and more female characters have started to appear as well. If Warhammer Adventures is setting a new standard then this is definitely a good thing, though they may still have a long way to go.There are more than a quadrillion humans in the Imperium (and who knows how many in the Mortal Realms) but yeah, they’re all cishet white guys 🤔 🤬— Gav Thorpe (@GavThorpeCreate) May 23, 2018
Recently, I have been trying to paint a few human models as non-white, as much because there was no reason not to. My Sisters of Battle and Blood Angel Shadow War Kill Teams both feature non-white models and I painted my Lord Ordinator as black.
Imagine if you were a 10 year old looking to get into miniature gaming having just read a Warhammer Adventure story. You just got one of the the starter sets and are looking for some paints for your Space Marines. Imagine you are looking through the racks of paints for some suitable colours. And now imagine you are not white. Wouldn't the range of colours labelled "flesh" send a pretty clear signal that this is hobby is not for people like you? That the company that produced them didn't even remember that you exist?
Miniature gaming desperately needs to move beyond the assumption that everyone is white and male. Warhammer Adventures are a tiny step in the right direction.
*I think my favourite stupid reaction is the claim that the character Kiri wearing a hood means she is supposed to be a Muslim. A Muslim in a fantasy world with no concept of Christianity, Judaism or Islam and which the actual Gods interact with humans and be bought in the shops and added to your actual armies.