This would be very exciting!
As creative as the bipolar idea would be, I would be happy with something as simple as the slop knob being completely replaced as a vintage knob. Yes, it would subtly change some sounds that I have made (as well as many presets), but I think I would like the change, at least for any patches that I've made that use slop. I feel that way because anywhere I used slop either subtly or drastically, the "vintage" aspect would be equally subtle or drastic. Having played around with the Rev4, I think turning "slop" into "vintage" would always line up with (or enhance) my intentions, at least personally.
However, I can see the desire to not have this alter any previous presets or custom patches. Because of that, maybe making it a global option makes the most sense if it can't be saved per patch. (Maybe that could be done by expanding the range of the existing "slop" parameter (e.g. doubling the range of the current slop parameter with the current range just being "slop" and the upper levels being "vintage," that could potentially leave existing patches alone and allow for new patches to use the new feature) but I have no idea if that's doable or not.)
Of course more options than just "slop" and "vintage" would be nice (like the bipolar idea or being able to adjust how "sloppy" the filters or the osc are getting per patch INDEPENDANTLY (e.g. the slop knob alone adjusts just the osc slop and a keypress plus the slop knob adjusts just the filter's slop)) - but I don't want to get greedy. I'd really be happy with anything.
Please correct me if I'm wrong, but we're just talking about expanding what get's sloppy with slop, right? That's why I feel like even just replacing the slop knob with a "vintage" knob would be musical in most cases.
(Obligatory "I made an account just because I am excited to comment on this.")