Answering the thread's question - I think eliminating something like slavery within a game that draws its inspiration from a period of humanity's history where slavery existed, would likely influence our storytelling and world-building to lose an aspect of gravitas and authenticity. That is how I feel.
aspect of gravitas and authenticity... maybe, if
you're actually treating it with the respect it deserves--and by respect, I mean to the actual people who were enslaved and who suffered, both in real life and in the game. And in my experience, most games don't
. The game may say that the slavers are Always Evil Kill On Sight, but it still treats the slaves
as just a checkpoint. If you freed the slaves, you get this many XP. Maybe. Assuming you're not playing a game where you only get XP for killing people, of course. There's no gravitas there, no meaning
, and certainly no authenticity. You free the slaves, no biggie, everyone lives happily ever after, while ignoring all the effects that slavery has on both the slaves and the society. How many games actually deal with that? Very few of them do. D&D doesn't. Of the games I own and have read, only Spire does, because the entire game is about
how broken, desperate, and ruthless the drow are because of how the aelfir have enslaved and abused them. You play as a drow fighting back against your slavers. But most games? Not so much.
Also, you mention "a period of humanity's history" while ignoring that, unless you are playing a historical game in actual earth, this isn't
humanity's history--and in most games, you have plenty of nonhumans
who, according to most gamers, shouldn't act like humans with masks on anyway. If you actually care about the worldbuilding, then make a world that doesn't rely on being just like Earth.
you lose an aspect of gravitas and authenticity, then OK. You lost one. But there are plenty of others out there without resorting to slavery.