I don't know... While it probably wouldn't make a full game (mind you I figured this would be a budget title at best) I can see there being fun gameplay there
The gameplay comes from attempting to play the economic game while at the same time fighting against the ramifications of slavery such as people raising arms against you.
By making your character a slave trader, you are condemning him to be a bastard
Yes that is sort of how games where you ARE the villain work most of the time. Such as Evil Genius, God of War, and a third example (I can't think of any... Both Legacy of Kain and Overlord you are just a hero who just happens to be playing the part of the villain)
However, in this non-existent slave game, in history terms, you'd just be a comma at best, the dot on an exclamation mark used by a person who hates you at worst. You won't even be remembered as the worst slave trader ever. They'll blame the society and the laws that created you, not you yourself.
Your ability to be a great slaver comes from how you exploit the world. Slave traders didn't go to locations pick up slaves at the slave depo and deport them. They were a bit more proactive then that.
You would be a great villain by massacreing villages and stealing their populous. Pretending to be friendly traders, then killing them.
There are plenty of famous slavers. MIND you, they are more famous for just outright killing people then for being particularly skilled slavers.
You'll make the best (noun) ever and always be remembered
Except SimLife, SimEarth, SimSafari, Flight Sim >_>
You will always be brought to justice in the end, and made to pay for your crimes against humanity
What? Heck no. Slavery was wide spread for a VERY long period of time (heck it still happens today). Who is bringing you to justice? is there some sort of benevolent diety on the high seas that I am unaware of?