Cs-80 is basically a "brass machine", brass keys, brass pads, brass basses, everything brass, ask Jim Brass if you don't believe me, hahah, so most likely in order to get that CS-80 sound one would need to model both oscillators and filters and maybe everything altogether, which again most likely is not worth it considering the cost of a unit and an appeal to the public.
Though I love it too, but now some sort of acid looks like an obvious choice to be added
