Ambitious project you have here!
Good start, I think. I, too, like the sword/weapon you have created. Anything to make a model unique
I agree with Evilgnome: the mask needs work. However, the other option (to adding more detail) would be to have less detail. Eldar have lots of big, smooth surfaces. You could turn the face into something more reminicent of a guardian facemask: the face smooth below the eyes.
Just a thought.
Good luck!
Rawson