The law of large numbers deals with the last issue. A much worse issue is that the aggregated rating is going to depend on the expectations that people had of

The law of large numbers deals with the last issue. A much worse issue is that the aggregated rating is going to depend on the expectations that people had of the product. And bad marketing can screw that up, especially if it attracts the kind of people that are a bad fit for the product. And the smaller you are, the more the 'marketing' is out of your hands.