The real problem with semiotics is a slightly different one, in fact. Hall and the gramscians were perfectly happy to admire semiotics all the time it was confined to exposing the ideological messages in contemporary forms of communication (like advertisements, films or modern spectacles -- as in Barthes' famous series of essays Mythologies). The underlying marxism of this early programme was a bit too close to Althusser and irresistible reproduction for British granmscians -- Barthes's work seemed to indicate that the whole world was saturated in ideology, and that only intellectuals, of a suspiciously elitist Eiuropean stamp, could escape. However, the Russian formalists semed to offer another good workable marxist approach, as argued by Hall in this piece -- the sign community contained traces of class struggle and so on. Of course, using such a source is itself a bit risky -- these guys were pretty much limited to a Stalinist politics, a rather vulgar form of the celebration of proletarian culture ( itself non-too congenial for gramscians uneasy with the racist, sexist and rather uncouth aspects of proletarian culture). Astute and critical reades might also want to know how this sort of approach avoided the traps of humanism and historicism which Hall had already acknowledged were undesirable.

However,the real problems arose with future developments in semiotics away from its cosy alliance with progressive forces like marxism and feminism. You'll have to read my more extended account in my 1996 book ( go on, force yourselves!!), but very briefly, semiotics turned nasty

1. it began to drift away from analysing the ideological texts of capitalism towards a more abstract concenr with texts in general -- any texts, all texts -- and to examine how texts fitted together 'on their own' as well as in term sof dominant ideology. This is what Barthes called his 'new semiotics' -- see file
2. it began to concern itself  with the dodgy signifying practices even of progressive discourses such as marxism and feminism -- these were merely texts, as was everything else. It was easy to conclude that marxism conviniced people as a result of its textual manoeuvres, and that these could be identified using the same critical 'de-centring' techniques that Hall is advocating here to expose ideologies. This terend led to the flight from marxism towards the 'posts' as I suggest.
3. such worries and anxieties also led to serious revisions of marxism, as in so-called 'post-marxism' about which Hall expressed later doubts. He calls this excessive, ungrateful, unruly and Oedipal semiotics 'Semiotics 2'