The WSM model partitions nouns based on paradigmatic information (which sentence contexts a noun appears in), rather than SUN's use of syntagmatic information (which grammatical contexts a noun appears in).
it is perhaps not surprising that the noun classes derived by the WSM are organised thematically, and the synonym/co-hyponym structure observed in the SUN noun classes is in many cases absent (e.g., {Pferd (horse), Reiter (rider), Stall (stable), Sattel (saddle), Stute (mare)}; these classes can easily conflate semantic roles (e.g., Agent for rider and Location for stable), which is presumably unhelpful for representing selectional preferences.