I kind of agree with AP. I have only personally seen race-blind casting once (I have not seen Hamilton, but would argue that it is not race-blind because it is intentionally casting ONLY characters of color), and that was in a wonderful production of King Lear at the Globe where they did indeed have Black and white actors portraying related characters. Everyone was remarkably talented and it felt very authentic because, after all, an Elizabethan traveling theater would have been casting the people they had, not...
Having Black families in the English aristocracy is alternate history and intentional inclusive casting. I don't see it as the same thing as raceblind.
Which has its place. Both do. I think we need both reimagined histories that center Black people and stories that remind us how terrible the past can be.