A new beta release for the Steam client includes scoped-achievements.
Achievements can now be split into game mode specific, DLC specific and seasonal specific achievements.
In theory, this will now allow players to achieve achievement completion, even though they're not interested in the multiplayer aspect of a game.
It would be cool if there was a way for community to contribute to categorising achievements. It's not like it takes technical skills, it's just sorting things into boxes. That way for old games with abandoned developers someone could still fix it up
Yeah, crowd sourcing is nice but it's probably a little more complex. DLC should be easy, as would be game collections, but devs can also buff up some of the smaller categories like multiplayer, which might have been minimized in initial release. Plus I think they want game competition trophies.
Even RA doesn't go beyond taking suggestions from community; they have an approval process for people who can edit sets, badge artwork and so on. With a for profit front end like steam, you add legal to the mix. Hopefully it gets the same support from devs as trading cards and emoji got.