Gygax's D&D contained the radical concept that the girl could be the knight in shining armor who slays the dragon. It's probably pretty hard to reconcile that with the realities of feudal life for women. Of course for Gygax it was pretty simple, his daughter wanted to play his game and he didn't sweat the details. It was also pretty multi-ethnic in the sense of all these fantasy races, and they aren't all at each others throats.
The original Dragonlance novels really embraced that idea. You have Laurana and Kitara as generals leading armies. You had humans, dwarves, elves and even a guy with a pretty substantial disability all working together to save the world.
Post-D&D RPG's in general have tried to embody those ideals, but they all sort of gloss over the details of how it works in practice.
Not only that, but it does not provide any significant information on how people actually react. Say you have a party of five well-armed individuals, some obviously magically capable. One thing that you would like to know is how they are perceived in typical social environments. Another is how they are perceived in the same social environments if they are all women (or if most of them are).
It's pretty clear in Sarnak, for instance, where any citizen will try to address women first and disregard men. It's not as clear in most other places - patriarchy, yes, but how obvious, how severe and how deep ? I would guess that things would be very different in, say, Aquitar, Haalkitaine, Kenezan and Varnost. They would also be different in the surrounding rural areas (Varnost perhaps excepted). But this is essential cultural information that is often forgotten or glossed over.
In the case of women you have to have some sort of support structure that gives them control over their monthly cycles, or their lives end up dominated by them. We do see some references to this in ShadowWorld, elves don't conceive easily, at the same time though humans are still just as fecund as they are here.
There is probably more than that, if only because of the abundance of tales mentioning casual infidelity. Sure, there are "accidents" and it means that contraceptive means are not all 100% reliable, but there must be some, otherwise the lineages of Rhakhaan would be the laughingstock of the world
And I guess that, as is often the case, more reliable means are correspondingly more expensive.
Is there more, though ? I was toying with the idea that elven women would have some conscious control over their fertility (once again, not necessarily 100% reliable), but it could be extended to non-elven races. After all, most, if not all, shadow world races are genetically engineered. It would not be unbelievable that they were designed with fertility control features. And while short-lived races would likely have forgotten all about it (or subconsciously switched the control off to offset a high mortality rate), elves would likely still have some knowledge of it.
It's harder for me to comment on ethnicity beyond there needing to a basis for cooperation as opposed to competition. The enemy of my enemy and such.
ShadowWorld can be a pretty dark place too, and there are some distinct examples of racism with underlying causality in the current works.
Racism does exist - my point is rather that there is very little information on how widespread and how focused it is, except is specific places (Stroane, at least part of Rhakhaan...). I would assume that trade hubs such as Sel-Kai and Kaitaine would be less race-biased and more social class-biased, but is it true ? And what about Lethys, a large trade hub with elven influence but also deeply Rhakhaani ? What about Ardania ? What happens when your multiracial, multicultural, multi-gendered, LGBTQ-inclusive adventuring party arrives in those places ? Who gets preferential treatment at the inn ? Who is mistaken for a slave or a servant ? Who is avoided by the commoners with half-hidden warding signs against evil ? Who gets singled out by local members of the opposite gender eager for a little exoticism ? Who draws the suspicion from the watch merely for being there, or is contacted by the criminal underground because of their skin color or ear shape ?
Not only is the information useful to better understand and play out the corresponding culture, but it has a side benefit that is important in my opinion: it puts a bit of the spotlight on aspects of the game that affect the characters beyond their technical features. It invites GMs and players to care about those aspects - to care about the setting.