thanks for the comment, and as to your concerns I'll keep those in mind.
Yes this is a very rough design, mainly intended to provide a cohesive guide to overall form. The most important aspect of this image is to make sure that all the planes actually make sense and can be built later in a 3d package.
If I do take the concept sketch further, have no fear. . . I will address your primary concerns. Fixing the sketchy lines and lighting issues for sure. Well, I'd do it at least until I get bored with the image.
I figured I should show off some of my rougher images so the massive influx of new people watching me (you included, if i'm not mistaken) could see one stage of how I design stompy robots and wooshy spaceships.