In your case, the committee members agreed that while the colouring technique was unique and interesting, it doesn't quite work with the Comic Genesis site design. We felt it looked rather lost on-site -- brighter, more solid colours seem to work better. Secondly, the Gen-chan only fills the upper half of the provided space; ideally, a Gen-chan should fill as much of the box as possible.
Back to the drawing board... eventually... :)
oops, I was going to link to the previous entry, but I'd hotlinked to the upload on their server, and I guess they deleted it when it was denied. So... too much effort to show you what they rejected, I guess. Maybe I'll up it to my 'misc' pics later. :)