Here is what you could do:
Once about five people have bought one yoyo, YYE sends an email to those who purchased it an ask, from a 1 to 10 range (10 being best), what they would rank the yoyo. Then, you find the average and post that on the site.
The only problem is, people look at yoyos differently than others. For example, someone may really like undersized and rank a Token as a 10. I, on the other hand, don’t really care for undersized (I do have a Token though) so I would say about 4. This would throw the average off a bit.
I, honestly, love the idea for a rating system, but I don’t know if it would work.