As admittedly implausible as the parallelism in the story is, I don't mind it, because it makes for a good story. The story shows how fascism, genocide, and war could've happened anywhere, even in America, which in OTL was spared from the worst excesses of the 20th century. I appreciate it for that theme alone.
Now, off the top of my head, some things I would change:
-I agree that the Freedom Party's platform needed to be elaborated on.
-Even though I said I don't mind the parallelism, I would've liked it if they did more to play up the ways in which Featherston and the Freedom Party are different from Hitler and the Nazis. There were kernels of this here and there in the story, but I would've liked to see more. Emphasize how Featherston had a different temperament from Hitler (in most cases, the Snake actually came across as braver, more hardworking, and less tolerant of B.S. than his OTL counterpart). Also, do more to explain the Freedom Party's ideology, and how their white supremacy differs from Nazism (whereas Nazism had an air of mysticism, claiming that the German race was destined through blood to rule the world, the Freedom Party racism seemed a lot more practical and provincial in character, basically saying that killing all the blacks was the most straightforward way of "solving" the Confederacy's race problem).
-Tell us more about what's going on in Europe! Turtledove created this very intriguing scenario there, with a German victory in WWI, a surviving Austria-Hungary and Ottoman Empire, an even longer and more painful Russian Civil War that ends with a tsarist victory, a monarchist restoration in France, and the turn of Britain towards fascism...and we barely hear anything about it! This was probably one of my biggest dissapointments, because I really wanted to learn more about what things were like in this ATL Europe. What is life like in the victorious German Empire, Michael II's Russia, Action Francaise-era France, and Churchill and Mosley's Britain? How do the citizens see themselves, their countries, and the world? What sort of rhetoric do the leaders use to rally support? Sadly, all of this intriguing potential was a barely-mentioned sideshow, and while I get that the story is meant to be North America-centric, it's still dissapointing that such a tantalizing scenario was merely glossed over.