Edit: Stop fooling with this foolish, non-working app. Just append this to the end of your search in chrome or FireFox:
&sort=review-count-rank

Courtesy of stackexchange
webapps dot stackexchange /dot/ com /slash/ questions /slash/ 36828 /slash/ filter-amazon-by-products-surpassing-x-number-of-reviews

It used to work, kinda, now it does not work at all, and the Github link is dead. The developer doesn't care, he just erased it from his site and turn the feedback / email off.... Adios Sayadzad wasted an hour of my time.