It’s a good introduction to the alternate history genre but later installments put too much focus on historical parallels for the sake of drama. Thus, how would you change any of these parallels? For me it would be not to go ahead with the Population Reduction. I get that the CSA was supposed to represent Nazi Germany and the blacks were stand-ins for the Jews. But the difference is that Jews were usually less than 10% of any European country’s population whereas in the Confederacy blacks usually comprised of anywhere between 20 and 50 percent of state populations. You would be killing off way too much of your labor force to be viable. Maybe instead you could transfer the role of Nazi Germany stand-in to Russia where anti-semitism was already rampant. In the CSA perhaps you could use divide and conquer among the black population and put them against each other or use industrial slavery if push came to shove. Note: I do not condone genocide in any fashion and this is just an exercise in alternate history.