On Marx as prophet and his writings as scriptures though, I stand by my point. If you look at the debates during the Second International period in the late nineteenth and early twentieth centuries, or those within the SPD during Weimar, there is a strong tendency among the participants to argue from Marx rather than from a broader perspective. That is, you'd get ideas 'refuted' by saying that they went against this or that in Marx's writings, rather than a genuine counterargument. Then there's the whole teleological aspect of the Marxist narrative. There I feel that Marx himself bears quite a bit of blame. All in all, Marxists seemed to often forget that Marx was just a human being who lived in a certain period of time, a brilliant one, but without psychic powers and quite capable of being wrong.