The discovery of the so-called 'Early Marx' via the first popular translations in English of the 'Paris Manuscripts', caused great excitement among marxist scholars in the 1960s, precisely because it seemed to offer a 'philosophical' floor to the more applied work on economics in Capital. To be very brief and schematic, Marx defined 'alienation' in such a broad way that it seemed to offer a way to describe cultural and social matters as well -- it stood for the loss of control over human processes including cultural processes. For some commentators, this led to a whole philosophy, or rather a 'philosophical anthropology', a general story of humanity and its fate -- constantly to create things and then lose control over them. Everywhere and all the time, this tragedy was unfolding, almost as a matter of destiny.
There were clear links with Hegel (see my file if you are keen), but also with all sorts of other allied philosophies -- existentialism, even Christianity. Marx had come home as a philosopher. At the specific political level, implications followed as well. Alienation was maximised in capitalism, and it became a priority to end it once and for all, by ending capitalism. Communism was practically defined as the end of alienated forms of social relations. More specifically, a politics associated with the Marxist theoretician and politician Georgy Lukacs, allocated a primary role to the proletariat in overcoming alienation and ushering in new, nicer, properly social relations. The proletariat would usher in the new era by becoming conscious of this role, by realising that their enormous creative power had been distorted and alienated in capitalism, but that a new way of life was possible.This belief that the end of capitalism meant the end of alienation was much discussed by Lukacs' contemporaries, including Adorno, who saw the whole scheme as romantically committed to some human destiny of reconciliation between man and nature. Other commentators wanted to distinguish between 'good' or even 'necessary' alienation associated with any act of creative construction of objects ( such as artistic objects) and the nasty kind found in capitalism.
Halls' critical references, to 'expressive totality' especially, refer in a coded way to this attack on Lukacs's conceptions of the social formation. However, Althusser led a later and better-known reaction to this kind of marxism too, and Hall is rehearsing some of his arguments here too. Althusser wanted marxism to be re-considered not as a philosophy but as a mature science, with special and distinct concepts designed to produce a definite knowledge of the world,not a mere moral commentary on its tragedies. Althusser proposed that we might find these concepts in the works of the later Marx, dismissing the early Marx as a juvenile pre-scientific phase, before he had thought out his own approaches. Althusser also identified the two great sins of humanism and historicism in work like Lukacs' (and Sartre's -- another early Marx fan). Very briefly, humanism insists that human agency (taking the form, usually, of a collective agent like the working class) can be seen at work in social change, as it pursues its mission to express itself (to end alienation and capitalism), Historicism is an allied error, which reads the path of history as following some pre-destined Great Plan -- towards the liberation of humantiy, for example.
Much scholarly debate ensued trying to locate the point at which the juvenile changed into the mature system -- where the 'epistemological break' occurred exactly in Marx, exactly what the key concepts of the new science were, and, crucially, it turned out, whether or not they were deployed consistently and rigorously in Mrx's actual work. They weren't -- and this led to the great disappointment in and flight from marxism among European intellectuals in the 1970s and 1980s, and their flirtation with far less 'scientific', more 'de-centred', even playful and irresponsible approaches like the various 'posts' ( above all postmodernism).