I think much of this is marketing, but fit is paramount. Proportionally speaking I've long legs, and several reasons why I need an upright riding position + quite short reach. My one WSD bike was sold at a loss because it was too big - if Trek made the 7.6 FX in a smaller size would that have happened? Unsure, but since the bike was too big it is difficult to determine if the problem was from the design or the bike just being too large for me.

If it weren't for my short reach I would ride a 52 cm frame, but for fit reasons I ride a 46-48 cm frame. That being said, my two non-custom bikes are unisex, not WSD at all (LHT and Jamis Dakar). I think the fit will still need dialed in on the Jamis, but I need to get more comfortable on the trails before we figure that out...

The point is to try everything out there, and find what fits the best. If an LBS won't show you non-WSD frames, then take your money somewhere else. In the end you might well need WSD, but you need to try all of your options.