I thought it would be nice to have the ability to sort your results according to the number of followers each manga has.
Since it is already one of the columns displayed, I believe it would be fairly easy to implement.
This feature interests me because I've noticed that sometimes I miss some good new manhwas/mangas that stay pretty down on the list when sorting with Ratings or Views, but often have a good amount of Follows. So with this it would be possible to make them more visible in Advanced Search.