Good idea Orpheus, a noobie rating would be great. Some themes are definitely more accessable to noobs than others.

Another thing that would be cool is to allow for a member to rank the theme on its variables: ease of use, layout, install proceedure, bugs etc. These rankings would not be averaged, but simply tied to the members comments on the theme. This way, there would be no need to try to have the highest ranked, or most downloaded theme. Everyone could see what others liked or disliked about the theme. I guess you could call it a "structured" comment.