Back then it would have been fair to give them payment for the years they worked for free (or shares worth the equivalent amount). It would likely have lead to a more equal society today. But we already fought a war over just freeing the slaves, I don't think giving them decades of wages at once was politically viable.

Reparations today would be an entirely different topic and would probably look more like social programs that seek to repair the lasting effects of the less than ideal way those people entered the (paid) workforce 150 years ago.