Yeah, the property delegation issue would be a sticky one. Because a key part of the system is that you have a choice to enter or not enter any territory. Well, natural resources and space constraints would make that difficult. But I'll leave that problem for the first real-life implementation of the Maximum Sovereignty system. And here's my rebuttal.
Communism is the masses serving for the common good.
Maximum Sovereignty is the masses are independant. Feudalism had few landowners. Maximum Sovereignty should have almost everyone being a landowner. Just the implementations that we've seen haven't worked. In some ways, this is the diametric opposite of Stalinesque communism.