You should know better than I, since you had a Prophet 12 and I haven't! Honestly, my ear has become so accustomed to stereo that any poly synth that has a mono signal sounds terribly dry, stiff, and lifeless to me. I figure the Prophet 12 hasn't been given a fair chance until it's been heard in either a six or twelve voice stereo configuration. That's my last hope for this instrument. No matter the sound shaping capabilities and sonic resources of an instrument, the mono signal kills it for me.
David, I don't think you've ever elaborated on your opinion of the P12.