I think you should keep the dark shadows on the one side of the sword, if you add any more lights.
Although an object "should" not always be centered in an image, I'd say that this sword "fills the height", that I think you might as well center it in the picture.
unless... you have some facinating background.
I also think the camera could be put even a bit lower, so that more of the sky is seen.
I do not support Bush! Nor Saddam! Long live UN!