I like the idea, would make for a very different playstyle for high ath characters. However, I'm currently getting 2 shot by like 4 ps katana users because of the speed bonus and the high wpf, adding an increased ninjaness and survivability on top of that would be a bit too much. Note that I have 60 body armor and 8 IF. If so speed bonus damage would need to be nerfed imo.