I would imagine that authors would get a much larger number of ratings if a simple "rate the story you just read" box popped up as soon as readers closed the story they just read.
And, giving a rating should not be a members only thing. Anyone who reads a story is qualified to leave an opinion, and membership is probably a deterrent to lots of potential reviewers.
Actually, restricting reviews to members only helps to prevent idiots from coming on-site and giving fifty people in a night '1' ratings. If a member does that, the moderators can do something about that when they downgrade the idiot to 'guest' status. At least, I assume they can. Tourguide?
Your idea of the automated review process would be a little bit of a pain in the ass to those of us who read with one hand, but it's worth considering.
The moderators of the forums have absolutely nothing at all to do with the story site. The only person at work there is Jinn. As it stands, you have to be a registered member to review stories, and I think that's probably a good thing, for the reasons Curtis gave.