I have a somewhat radical, sadly not novel suggestion: build what you're looking for.
I now have a semi-private "HN Reader" which has completely broken my HN habit while still feeding me stuff I might be interested in. Because I built it, I can make it do anything I want. I've started to turn it into a slightly broader search engine so that I can find the things that I'm looking for; I got sick of seeing search engines brag about the hundreds-of-thousands or millions of search results they were returning when I was trying to find something (really, what's the point of that?), so I'm building my own. I got sick of feeding some psychological trigger in my brain that made me nervously check the HN front page numerous times throughout the day, and I'd find myself clicking on items that had lots of comments and activity even if the subject was something I wasn't interested in. I guess I was thinking, "wow, lots of people over there, I should go check that out."
What did it for me was a bit of foggy nostalgia one day. I was thinking about "the good ol' days", how I -- we, all of us if we were lucky enough to be born at the right time in the right environment -- used to modify the crap of out of programs, change their interface, tweak their colors, cheat at games even when we were the only ones playing. We used to take things we didn't like and turn them into things we did like.
But nobody, or very few people, do that for the web, even though there are piles and piles of tools that make it easy and doable.
So I did it.
And it is glorious.
It's some of the most fun I've had at programming in years. Now when I'm feeling like a wet cat, I'll just go tweak my little reader-search-engine-toy, and then I feel better. Now I never feel like I'm missing out on something on HN, because my little toy is keeping an eye on it for me and saving the stuff I might care about it.
And if you're looking for a new community ... well, build that too! It's clear from numerous threads on HN and other places that people are ready for something new. Make what you want, share it if you feel like, if enough other people like it maybe they'll join in and you'll have your community.