Well this would be incredibly useful in cutting down most of the time required to make sprite sheets if you have skills in modeling and animation. I dunno about it ruining the craft of spriting, but, there are just some things that look much better sprited by hand instead of using this filter. Think about a filtered Kirby or Megaman sprite in a game with sprited backgrounds. Sure it would look nice, but you would loose the benefit of using a custom style/shading that could only be achieved by hand. (unless there's a way to filter that too...)
Just my thoughts.
Just my thoughts.