It's a little more complicated than -- there is more fabric at the crotch of a pair of pants than there is at the same point of a skirt, so the zippers can't just go up the inseam of the pants—I think they would have to continue past the crotch without being zipped that far in pants form. Comfort shouldn't be too much of a problem with a reasonably relaxed fit and good, thin zippers. There's also the question of what to do with the extra fabric to make the skirt flare when they're pants; my inclination would be to put it on the outseam, with straps to keep it bundled up, but there might be other options.