Just my opinion, but here goes:
OK, the right corner of his mouth (Sasuke's right) shouldn't be too downwards-pointing, otherwise, it looks like he's had a stroke, or something. So I think the mouth should be lifted somewhat - straightish. His eyebrows could be straighter or more in sync with one another, instead of doing their own separate thing, if ya know what I mean~? His left eyebrow seems to be really pointing downwards. Perhaps if it could get a slight lift?
Man...I feel like such a nitpicker, esp. as the colouring is so awesome!
Er...why is DA strictly prohibited? Just curious.