I like the simplicity of the drawing. The background you used (white box on black bg) will help accentuate the colors whenever you get around to coloring it. I love the way you used the black and white contrast around hair and the coat collar edges of the large face (Aoi Hamazaki, I believe).
The characters themselves mostly look good from here (it takes my comp forever to download, so I'm looking at it standard view now). Details are present at all levels of the scan, not just on the foremost characters or anything like that.
You say that your drawing is really starting to suck with proporttions and the like, but I must disagree. I'm no expert by any means, but I only see one thing that doesn't seem to match up. I believe it's Aoki Yatsuka's left leg (on the right from my view); the frontmost character. It looks as though you were trying to put it further back in the drawing, but it just looks...I don't know, wrong. Anyway, that was the only problem I was able to notice, personally.
I like the way you drew the weapons, personally; they look realistic, as far as this kind of drawing goes. Anyway, I'd love to see a colored version of this; good job. :)
