Would it have been plausible--with the right leadership in Germany after a German victory in WWI--to have the United Baltic Duchy (Latvia plus Estonia) become a cosmopolitan independent state?
Specifically, I am thinking of not only having nationalistic Germans move to the United Baltic Duchy, but also having large numbers of Poles, Jews, Ukrainians, and other ethnic groups move to the United Baltic Duchy--thus gradually making the United Baltic Duchy very ethnically diverse and cosmopolitan.
Anyway, any thoughts on this?