This happened in a League of Legends bot that I worked on - scripts would be voted upon, and on the equivalent of the SDN, would be displayed according to the number of upvotes. However, when new scripts came out, they never had a chance because everyone just downloaded the most popular one (even if the newer one was of better quality). I think a possible solution to this is to have some sort of up vote system which is reset every month. However, it would have to be monitored pretty well to prevent vote manipulation (i.e. scripters requiring users to upvote in order to get a script trial, etc.). With this in mind, however, it might be more work than it's worth.