Henri Christophe
L'empereur
Are you talking about the Bandeirantes? I still believe it should be Brazilian Unique Unit, not because they are hunter of slaves, but because they represent very well brazilian heritage, Brazil have big boarders because of the exploration of Bandeirantes.That only appear at the tail end of the game. The mechanic is just as unfeasable and un-marketable as your Brazilian slave-raider unit turning defeated enemy units into new workers from a couple years ago.
And Bandeirantes don't did nothing than the other Unique Units don't made, as for example Spanish Unique Unit, the Conquistador, also enslaved people and it is in the game.
If you want to discuss this again, the thread is here: https://forums.civfanatics.com/threads/brazil-unique-unit.665609/