I think the real question is, is this story, torture porn or not?

If that is what the story is about,? logline actually works.

A mean white slave owner switches bodies with his slave, and then the audience watches in glee as the former slave owner is beaten, whipped, degraded, and abuse, end of story…

However, if this is a morality tale, then you need to give your lead character a goal.

So what goal would be the irony of ironies?

Perhaps after he is transformed into a slave, and beaten by his former slave turned white, he must escape and find the underground railroad, the very people that in the beginning of the story he called traitors to the south.

And on top of that all his slave owner buddies are now after him with dogs and shotguns, and he realizes that skin color is just that, and nothing more, he is still the same person on the inside but just because his skin is now black he is seen as less than human.

Perhaps the key is crossing the Mason Dixon line.

Once the lead character crosses the line into the north he’s is changed back, but with a new perspective on race and what makes a person human, because the people who helped him were more human than his former friends who turned on him the moment his skin changed.