I can't seem to shake the feeling that he seems too cartoony. Maybe it's the big eyes or the high cheekbones. Maybe if you made his eyes smaller or something. Also remember that the Vong have scars and piercings and stuff like that. Maybe you could pierce some of his fingers, or put little razors instead of nails and stuff like that. Now, if you could make a crab-armor to go with it, you'd rule the world. And Larry, the Yuuzhan Vong are definitely NOT on our side.