WoTC seems mostly concerned about problematic societal norms, but not about individuals being evil.
I don't remember how Dark Sun worked, but the most future-proof reboot I can think of is to reboot slavery as a pact/bond with the dragon kings.
So basically, everyone has a warlock-like pact with the dragon kings, except the lowest class get nothing good in return and only bad things from being bonded to their dragon king overlord.
The tvtropes page for it does an oddly thorough job if giving a short summary the highpoints in "contains examples of" section because the setting squarely hits so many tropes involving morality & dark fiction.