I am both a gamedev and a avid game player, of some niche and strange genres included.
I found out that Steam catalog, despite "opening the floodgates" is quite limited on some genres, some niche genres have the nicest games don't even volunteer for steam (usually because the nicest games have perfectionist devs that don't want to be "another shitty early access", for example Starsector, the game has been being sold in pre-release form for years now, but the dev flat out absolutely refuses to get on Steam, because he thinks the game ins't ready for that), and even when they do, they don't get enough traction with the public to get through Greenlight or to skip Greenlight.
On some other genres, you will see loads and loads of crap shoveled at you, but the good games still don't fill completely the recommended games section screen...
The only thing I think Steam can do differently in their interface, is make the "order by public rating" easier (this feature actually exists already! But is mostly hidden, every time I need it, I google around until I stumble on it, and each time I end on it by a different path!), usually when you do that you see a list of actually great games, mixing both truly great AAA games and actual underdogs (example: last time I checked for some genres, I owned all games on the first page on the list, some of those games I know I am one of the few people that own them, because they are not widely known, while others are full blown 100 million marketing AAA).