What's amazing here is the complete lack of bowl-cut. I think that alone drives me off the wall.
Luckily the Sisters I created ([link]) have none of that. While I understand the textures look flat, I think your strong point here lies in her face. It's not one of vitriol. It's one of contemplation, something nice for a change.
Heh...well actually the artist is Chaotic-AlterEgo, so all skill credit goes to her. The concept idea of the Sisters however belongs to me. I wanted to create more unique looks to them, especially with the Order of the Valorous Heart scheme (real GW order too btw). I wanted to create some without the bowl-cuts or the bland design...not to mention in the future personalities that aren't like that of a voice recording.
I only recently started to appreciate the sisters as part of the 40K universe. In the past I dismissed them as fetishes to attract 14 year old boys. But when I started GMing Dark Heresy I had a player want to play a sister. And reading through the "Blood of Martyrs" got me fascinated with the Ecclesiarchy as an organization. So I'm seriously toying with the idea of a Sisters web comic at this point. But I don't want to do something typical of the usual fanboi sister worship. I want to do something with a less militant order, with deep personalities and a well written plot.
All you're going to get is nothing but the call of "fanservice" if you do. I had designed Gabrea, Cassia, and Maeve to specifically have actual personalities. The Order of the Valorous Heart is pretty much Orders Militant but they're not the damn typecast Sisters. Granted, they're but a part in the greater story of the Librarian vs. Chaos, but they were meant to actually show something beyond "GHAAHHH INNOCENCE PROVES NOTHING BURNNNN UNBELEEEEEEEEEVERRRRRRRRZ AND DONT TOUCH ME MEN." The three of them, different positions mind you, have their interactive personalities and some semblances of humanity.
Ciaphas Cain's story in Cain's Last Stand presented a veteran Sister who played cards, drank, and wasn't celibate. I won't make it that casual but I hope you could take a note from it.
I'm not communicating myself if you think I'm talking about fanservice here. I'm talking about gritty 40K with believable characters. Doing for the Sisters what Horus Heresy is doing for Space Marines.
Sorry...I was just being cynical. Typically when people do Sisters, the drooling masses tend to treat it LIKE fanservice. I know you've got a more creative angle up your sleeve. I'd like to see what you've got in mind and maybe I could tell you mine.