Perhaps the reason they didn't include small weapons this time was to simplify the system. If Milo the Halfling Fighter for some reason needs to trade off his Longsword off to Tordek then Tordek immedately knows what he can do with the weapon. But if instead he handed him a Small sized Greatsword then there's extra rules explain that it can be used as a versitle weapon by medium sized characters, explainations as to why a small sized longsword can only be weilded in one hand by medium sized characters, etc.
Just makes for a smoother system this way.
Just makes for a smoother system this way.