i do think that one thing that this discussion about width is generally missing is how the effective edge length and radius play into it all, as well as overall length.
the "surfy inbounds powder ski" aka 112+ classification has high rocker heights, short effective edge, and short radius (s7, w112, JJ, etc)
the "freeride all mountain" aka 10x class of skis is typically longer-ish running lengths, less rocker than above, and generally available 190+ and generally large radius (27-40m)
the "all mountain" 98mm class generally has long effective edge lengths, mild rocker profiles, but typically has a shorter radius (say, 20-24m), and generally shorter lengths (bones = 187 max).
so when comparing these classes of skis:
*the 98mm will generally carve a little cleaner, but that has as much to do with a narrower waist as it does a tighter radius.
*a 10x freeride DD class ski (say cochise) might float pretty decently compared to a rossi e98 for example, but compared to a S7 or W112, its a bottom feeder, and certainly less maneuverable in tigher trees given a 25% longer effective edge, and a 27m radius vs. 18m radius, not to mention requiring far more speed to plane.
all that said, i would likely be equally happy on a 98mm waist width as a 105mm waist width as an everyday firm-ish snow ski, but radius and length due factor in as much as waist width, and where i live and how i ski currently says a 190+ 27m+ ski makes the most sense.
just thinking out loud, but really like this thread.