Exactly how can you tell if the recommendations have actually improved, and by how much? I can see how you can improve it, but how can anyone quantify it? If a recommendation is "good" or not is entirely in the eye of the beholder.
I've been hoping they would improve their rating system somehow. The first thing I would do would add another "star" or two. There you go, I improved the rating system by 20%. I win! Now where's my million dollars Netflix?