First off, your robes are well done. The added texture provides depth and believability to the robes, which originally looked flat and lifeless. As for the mask, while you've succeeded in making it look more iconic and dramatic, I think that the high contrast, graphic look of it doesn't fit with the new robes (even though it works perfectly for a dramatic cutscene or iconic promo poster). While the new robe has more detail than before, the cloth under the mask now has less detail. I saw this screenshot (
http://i47.photobucket.com/albums/f157/strwars137/Darth_Nihilus.jpg) which shows half his face in shadow, but the other half is highlighted to show the detail (I'm guessing that it is an action figure).
I realize that this is a stylistic choice, but IMHO I think that somewhere halfway between the original texture and your new one would suit it better.
As for the detail up and down the middle of the mask, it looks like you've just widened the texture, and it doesn't match the model anymore. In the close-up of the face (screenshot #6) it looks like double vision on that circle part. Have you considered modifying the model to re-shape the white part of the mask? So far, I've seen some nice texture work from you Drewton, maybe you'll do just as well at modeling.
Keep up the good work :)