The reward system doesn't seem to be working to your advance. After only 5 sites I was done. This doesn't allow me to earn a lot of feedback points.
Also, I think you put too much trust in people rating reviews fairly. Anyone can be easily offended by critique and thus downrate the review. While in fact it may be their most useful review so far.
I don't have the exact solution here, but tuning your reward system is likey to increase activity on FeedbackRoulette.