Honestly I don't even like the term WSD. I'd rather see them identified by what actually makes them different, smaller frames, narrower bars, whatever. I'm friends with a guy who is fairly short and really struggled to find a touring bike that fit. He probably would have done well with a WSD bike, but it didn't occur to him to look at them, and it didn't occur to bike shop guys to point him towards them. If they'd been labelled purely by size he might have checked them out.