3DS eShop was never that good despite the installbase. Likely too hard to port over most indies so it's not super surprising
The 3DS's store was slow and hard to navigate. It also didn't do a good job of helping you find the game which were released since your last visit. The Switch's store is better than the Xbox One's store and the PS4's store (that's not saying much because both stores are meh). Here is why the Switch's store is better:
A) It's faster
B) It's simpler (less work to get places)
Here is where it needs to improve:
1) Like every other store, it's basically a database front end. Real stores help people find the best content on the system. They have humans who go through all of the games, find out which ones people love and highlight them so other people buy them,
2) It needs human game categorization (never let publishers categorize games because they will do stupid things like claim Ninja Gaiden 2 is a "fighting game").
3) It should show people how long
paying customers play games on average. It should only include customers who started the game and played for at least 2 minutes.
4) Nintendo should use system telemetry to determine which games people like and promote those games.