It's a great sig, overall. Since I'm not exactly the most well-versed with the visual arts, I'm not much of a critic. However, for what it's worth, I will throw in one suggestion/opinion/whatever:
The character in the sig (a Night Elf, obviously) is a very graceful, very "soft", if you will, figure, whereas the background and rest of the sig are quite harsh by comparison. I think that it's a good background to match the kind of character you're featuring in your current sig (I'm assuming it's Arthas, but forgive my lack of WC3 and WoW knowledge) - a character with a very hard appearance (lots of sharp edges and cold, uninviting features on his armor).
That mix, imo, doesn't suit the more gracile form of the Night Elf character. That's not to say you can't pick a motif that makes your character look badass; it's just that I think it would blend better with a softer, less... "gritty" background.
I don't know if that makes any sense as, like I said, I don't often critique stuff around here, so take it for what it's worth