You are bringing two issues.

The first issue is the display of uploads without rating placed affront of (in the rating sort) the uploads with 5 stars. Those uploads were rated 5, but we were not displaying their rating as long as they not have at least two rating entries. That logic was missed from the original sort and we addressed that issue. Please check it .

Regarding the second issue of the rating itself. Currently we are using simple average.  we are open to any reasonable change and will consider changing the logic if it is doable and fare to all members.