One thing to consider is that they PPG Wave and Prophet VS used two very different approaches to wavetable synthesis. The PPG had tables of waveforms where there was a gradual change in harmonic content from one waveform to the next, which meant that stepping through a table resulted in a smooth'ish sweeping sound. The Prophets VS, on the other hand, had no such arrangement of the waveforms. Instead (adjacent) waveforms were radically different, and this was much of the point as the 2D vector envelope mixed 4 of these waveforms to make smooth transitions between them.
Thus, sweeping the VS wavetable in a PPG fashion will not yield anything like the PPG sound, but rather a jumble of very different spectra. Of course, that in itself could make some cool sounds, just nothing like a PPG.
For the very good reasons mentioned by philwick, i.e. the memory capacity of the TS-203 DSPs, I doubt it will be implemented. Instead, given a quantizer module (on my Origin wishlist...), one could make a stepped sweep with any of the Origin filters and get close to PPG-land that way - well, not really but at least one would get gradual stepped changes in harmonic content. It would also use very little memory and be computationally cheap.
DJ
--
