I gotta admit, I think that having 5-6 mods showing per row is actually great since (I am taking a guess based off of what I've seen, and others comments) the vast majority of people use Nexus Mods on a Computer, or a device with a larger screen size.
Optionally though, a button in the search menu to toggle a more 'mobile' (bigger images, mods taking up more space for visibility, etc) and a 'pc' (more mods per rows, smaller images, etc) would be really helpful!