I would be interested in the Prophet REV2 sixteen-voice even if it was mono-tymbral. One of the most annoying shortcomings of polyphonic synthesizers, due to the paucity of voices, is the resultant "pop" of voice re-assignments. Sixteen voices would put you above and beyond that shortcoming. Consider left-handed arpeggios, which can at times cover the entire five-octave range. If you're playing a melody with your right hand and an accompaniment with your left, it's easily possible to strike and have ringing from eight to ten notes. With only eight voices, the ninth note will rob you of the first note, which is likely to be the lowest and the root of the chord - the worst note of all to lose.
This is only one example of the benefits of having sixteen voices. In bi-tymbral mode, it's even more true that the more voices you have, the greater the musical potential. On my eight-voice Prophet '08's, I'm constantly running out of voices, especially in bi-tymbral mode. It's a real problem that I'm expecting the Prophet REV2 will at last solve.
If all goes well and I'm satisfied with the instrument, I intend to eventually get two sixteen-voice REV2's. If I get an eight-voice, it will be as a part-time monophonic instrument.