Probably that, The_Sibelis, or something that will become relevant in MM.
And yes, WWW, every time that the weight of the sword is mentioned I was intrigued. I have 0 experience with swords but it seems that fighting with essentially a handle in your hand, no weight for the blade, would be a difficult task. Yet, once you get used to it, it is be very convenient, as you don't need to pass a strength check to wield it, you don't get tired, and can be very fast. All very useful for the not so strong adventurer. But still, I wouldn't think that the skills needed to fight with such a weapon should take more than a month. As I said before, I am willing to cut JB some slack as the sword itself could be helping.