Quote - Spheres -> weight maps would be trivial. After all, Poser and DS are in effect doing it already, it just needs to be output to a vertex map (which is just a list of values for each point). However, I believe that many if not all weight-mapped systems use a single set of weights per joint while Poser rigging has separate weights for each parameter - however, even if that's true there's no reason a new system shouldn't use a map-per-parameter (if you wanted the same values in each it would be a simple copy and paste at worst, and perhaps just a tick-box at best).

IMO the 3 joint-zones are a good fit for poser's euler-angle posing system (not that i am friends with it). With weight maps, you really want to have only one value per joint, not three, so when switching to  weight-mapped posing, it is very likely and advisable to disband the euler-angles for a slightly more unambiguous system, e.g. quaternion rotations or axis-angle, so that multiple maps would not be needed. Everything else would probably be sheer nightmare-horror for content-creators.