I feel like some software/platform features that encourage and foster more community-based and discussion could go a long way.
Some quick thoughts:
user-specific multi-communities
Being able to notifications for certain events or activities (incl special notifications from a community or ongoing discussion in a thread)
Opt-in post visibility, such as excluding a post from the All/local feeds (similar to the private communities feature coming to lemmy)
Perhaps controversial … but expanding into a quasi-blogging direction where people can have their own personal communities into which only they can post, a little like microblogging, but more like an actual blog given the character limit here. Along with multi-communities, it could be quite a nice complement and allow for communities to evolve around people with interesting ideas/thoughts.