I don't think the eShop interface is too bad, it's clear and simple to navigate, but they definitely need to make huge changes on the back end in terms of discoverability. The cash grab spam issue is a major one that needs to be addressed but even if they excised all that stuff it would still be hard for most games to get noticed so I guess a review system that is tied to your NSO account would be a good way of highlighting quality titles without the cash grab devs being able to exploit the system in their favour.
Besides that though the main thing for me is the speed, it's so excruciating to navigate it at the moment if you're looking through the games that are on offer - I've got used to it over the years but I would probably go to the eShop a lot more if it was a smoother and snappier experience