Those hips don't lie.
But in a full Critique here's what I think:
With how the back lighting is done and the spooky fog effect it really creates the effect of what a darkened Lordaeron might look like in real life and that's fairly key for the presence of a Sylvanas character because it's not often in WoW we ever see Sylvanas outside of Lordaeron.
As for the costume itself I think it looks great. It's a very sexy but functional set of armor for the most part and looks like something Sylvanas would in fact wear. The difference perhaps might be that the footwear wouldn't include a 6inch high heel but more of a Belted goth boot, since Sylvanas is undead afterall. Also for a future photo of this character, I think having your skin body painted to a much paler color would really complete the undead state of the character, which is very lacking in this shot. Also if you could get a hold of some of those really big elf ears that the blood elves have in Warcraft (WoW lore. In previous Warcraft games they were the High Elves and they didn't have gigantic ears.) and get them to poke through that hood just a bit you would have completed the elf side of this character as well.
And finally to complete the Sylvanas look, she was a elven ranger and had a bow and arrow quiver, if you could get an arrow quiver at least to wear on your back we'd see that old ranger that Sylvanas still is, even in her state of undead-ness.
Overall I find this to be a very sexy and mysterious photo, and it just needs those few extra things to complete the portrayal of the character.