The opposition to Marx echoes here the historicist critique (seeGustav Schmoller) of the possibility of theory: there is no real possibility of creating an abstract economy/bourgeois mode of production for the purposes of making generalizations and discovering laws of tendency. Of course to jump to political consequences this is a most damaging, roundabout way of critiquing Marx's claim to discovery of several laws of tendency about the capitalist mode of production. The turn to hermeneutics and the obsession with meanings probably had the same motivation and consequence--that is, a rejection on methodological grounds (by say Dilthey) of speaking of any necessary long term consequences of a mode of production in terms of a materialistically determinist theory. That is, we have to return to the old defenses of historicism and hermeneutics over and against Marx's kind of scientific theory to understand the reasonable reaction to Marx's theoretical project.
The underlying idea here is that the system is just too open-ended to speak of even tendential laws and that any work of economic theory is only possible by abstracting away from the state, the reintroduction of which dissolves the law like nature of any economic tendency.
What is then left is the possibility of detailed empiricist study or a kind of social theory which discloses to us how actually open ended the system already is.
For those who are not historicists, perhaps Roberto Unger's vision of the possibilities of social theory and the plasticity of institutions captures best what many people see as the limits of Marx's kind of theorizing. Unger's is a powerful vision indeed.
Rakesh