Can you post a picture of it on the loading screen, cant tell if its green, black, or purple (or all) ALso, what are you looking to improve specifically?
A great choice of armor for a necromancer, but what ever is it your necromancer is, is lost with that mask. I'd love to see you put something together, using some of the same armor pieces minus the mask that work with your character. Play off the color of his skin, and grab a screenshot somewhere with better lighting to show it off!
I like your set as it is, but if you're looking to change things up, sometimes the Sylvari cultural armors look surprisingly good mixed with normal armors.
Try previewing the T3 helm, shoulders, gloves, and boots with that chest and legs, and see if you like it. I think it might look pretty neat. Just be aware that the T3 Sylvari armor can be tricky to match dyes with other armors.
Dry bones! One of my faves. Darker black might help it feel like a more badguy set overall. I honestly went midnight fire with mine (basically abyssal red) and it worked for a warm death theme. Staying closest to green, maybe a midnight olive or yew. Midnight Ice may be too blue for the look you're going for, but one of the other midnight dyes with a tint towards your color scheme might work better (and cheaper than flat out abyss by far).
I know others are against the mask, but, I gotta say its one of my favorite parts of this set. It fits with the Karka shell really well and makes your character more elemental looking. Not personable, perhaps, but YMMV.
I honestly went the 'drybones' helm/chest/legs with mine as the patterns and textures seemed to match up better. Whispers was my other favorite set to work with. Gaunts and boots I went CoF (because FIRE! :D), but you could roll a gaunt/boot combo from a lot of the sets and swap out till you find the look you're going for.