really good stuff here once again. it has been mentioned in other threads, but it bears repeating how great it is that everbody is chiming in.
now obviously my "experience" comes from 10-15 sheaths only and some random other stuff, but here we go:
i would personally go with softer to the touch, but like anthony i don't really get that touch after dyeing and wet molding. then again, after reading horsewright's comment i agree. in hindsight it might have actually done me a service that the sheath came out stiffer than expected. better retention and as i like to carry a small fixed blade in my pocket it most certainly helps to prevent stabbing myself.
i also think that there is some kind tension/whatever involved in the stiffness of the material. a wetmolded sheath seems stiffer to me than a bracelet that has been wetted (both of the same weight of course). maybe because the bracelet can move around and the sheath is sewn together at various points, i don't know.