I've been getting into Postone recently and it's everything I wanted from an interpretation of Marx. It highlights all the best about Marx as a critic, while bypassing many of the pitfalls of 20th century Marxism that were criticized by poststructuralists.
Postone views Marx not as proposing a metanarrative, but as proposing a critique immanent to capitalism. Baudrillard criticized Marxism for unjustifiably positing the basis of capitalism (labor, productivism) as the basis of all societies.
But on Postone's reading, the category of labor (as well as Value) is a category immanent to capitalism, and needs to be critiqued as part of it, rather than be taken as a standpoint from which to launch a critique. It's not meant to be applied trans-historically.
That way, Marx doesn't have to be read as positing a universal human nature as the basis of critique (the nature of the labourer). Rather, the universalism in Marx comes from the globally and artificially imposed condition of being a wage-worker, which is unique to capitalism.
Nor does he have to be read as proposing a metanarrative. Rather, he's proposing a critique of capitalism that is immanent to capitalism itself, and will be overcome as capitalism is overcome.
It's important in general to note that most 20th century understandings of Marxism came from Engels, whose popular works after Marx's death were quite different in many ways from Marx's own. And those views were further shaped by the 2nd international and then the Soviet Union.
It is in those transformations that Marxism became ossified as an economically determinist metanarrative.
