Selfhosted

I'm not really sure how a decentralized storefront would work? Where would the game files be hosted? Do you mean like a federated solution, that shares the encrypted game files around per instance? Or true decentralization where there's p2p hosting, with the devs having to run their own hosting originally before players pick up the game? The former I could see working, the latter not so much (smaller devs often don't have a 24/7 server to run for this sort of thing).

In terms of gui/client, I wouldn't mind one that let's me manage my games and isn't "locked down" to a particular company. For instance I have both steam and epic games launchers, why can't I just have one launcher that works with both storefronts?

In terms of features I want for a library/store client? Options to easily access the game's install folder. Mod manager if applicable. I'd like an auto-update feature. It'd be nice to have crypto payment options (not as required, but optionally if devs/customers wish to use). I'd like it to be able to track games outside of the storefront. For instance, so I can log what switch games I own (even if unplayable on pc). Easily able to rate games, manage my reviews for them, categorize and curate game lists. Howlongtobeat support would be cool (or it's own game time tracker). I love seeing how long it takes to beat games, and don't mind contributing my times (and logging it for myself). Tracking play history (what days/hours, how long, which games).

Steam has a lot of good features. Having a customizable profile page. I wanna be able to quickly share with people my gaming tastes/preferences, have a little customizable profile thing. Find others into similar kinds of games. Groups are cool, but idk why I never feel like it's worth it to contribute to steam groups (either feeling unwelcoming, or they're dead lol).

Stream/viewshare options. Along with making it easy to jump into multiplayer with someone (either joining existing play session, or starting one together).

Tagging/categorizing/recommending games is very important, especially for a storefront. Steam's system is dogshit for finding games I wanna play; mostly because the user tags end up mistagging a game entirely. hentai games show up for the "otome" tag, games like hello kitty get tagged as "horror", etc. making them basically undiscoverable.

Stuff I don't care about would be things like those steam items/unlockables, achievements, trophies, etc. So many game platforms do this and I just don't care. I wanna play the game, with friends if multiplayer, and I wanna find new games and share what I'm into. don't nag me about some item shit I don't care about lol.

One thing that'd be cool is having an out-of-game item marketplace for player economy. For instance we see sites like https://nookazon.com/ pop up as a dedicated website. why not have that as a built in feature to the client?

I don't care for "curators" other than on a user level. I run a steam curator page myself, but I think this sort of thing should be per person/account. Let me recommend a game or put a little thought about it that I can share with friends or others with similar interests.

I don't care for steam's "game community" thing. They try really hard to have a sort of mini-social-network for each game where you can post comments or screenshots or whatever. In the end, no one uses it seriously and it's just spam.

Basically: I just wanna be able to manage the games I own, track the games I have outside the platform, track my playtime, show my game preferences, easily connect with friends, and watch others or jump into game together. Steam does this pretty well in most aspects. They have a lot of fluff but that's ignorable.

epic games, in comparison, is just bad. the ui is laggy and slow, it's ugly, there's no way to curate what I like or categorize things, there's no way to share my tastes/preferences with others, there's no way to discover interesting new games. no way to manage mods.

ultimately though: there needs to be games, or a way to track or launch games that aren't sold on the platform. steam lets you add non-steam games to launch, but it's awful, annoying, and sucks.

also fix tags/recommendation/discoverability. I like niche stuff that people unfortunately feel the need to troll on, so discoverability ends up being difficult.