I agree with you (it must be Christmas
) and it has been suggested several times. Also that in search and browse results Free/Standard listings without thumbnails should show after Gallery/Platinum listings with thumbnails to prevent reams of image less results being shown.
Sellers pay extra to have the thumbnail so that is a justification for being given prominence in results; just as FrontPage/Featured listings have prominence over others. That is in addition to the case, as you present, of making the site more appealing.
As admin have never shown any interest in the previous suggestions you may be administering punishment on a recently deceased equine.