The past is a foreign country: they do things differently there.
Which way do you go as far as using social conventions in your game world? Humans are not nice to each other. Reading history is more shocking than any horror movie could be. Forget about the large scale horrors of genocide and colonialism and war - even more mundane elements of past societies - the degree of racism, slavery, sexism, casual attitudes towards infanticide or child abuse - are revolting to the modern person. (I hope they're revolting to the rest of you, too).
So the question is, how much do you aim for historical verisimilitude in representing your fantasy world? I suppose I can see a number of common positions. One is to put all the historical elements in place, and turn the past into a foreign country - the players need to learn the social conventions - "Slavery is okay here!" - in addition to adventuring. Sword and Planet stories, right here on Earth!
Another approach would be to use anachronistic, modern social conventions - women and children aren't just property, for instance. Modern players then don't need to grapple with social problems and can focus on adventuring.
Finally, in a fantasy world with an alternate power structure than 'might makes right', there doesn't seem to be any problems ignoring real world social conventions. There are many leading female characters in fantasy worlds that don't have to deal with glass ceilings and double standards. Magic is a great equalizer.
I see myself working more in the quasi-historical space going forward (not the Black City, mind you, that's 100% fantastic) so it's an interesting question to me.