I was going to say something very similar. I've been irritated by repetitive content / themes, but a lot of that is simply because I've read it many times before - it's not necessarily a sign that the community is getting stale, it just means I've been reading it way too much.
Interesting point about the community growing more specialized - I thought that HN losing its focus on startups (circa the Startup News -> Hacker News rename) was overall a negative thing, since that's what attracted me in the first place, but in retrospect it's probably not. I think I would've got bored much faster reading effectively the same posts about startups over and over again. The wider scope has probably helped to keep the site fresh for me, at the cost of somewhat lower signal/noise.
Interesting point about the community growing more specialized - I thought that HN losing its focus on startups (circa the Startup News -> Hacker News rename) was overall a negative thing, since that's what attracted me in the first place, but in retrospect it's probably not. I think I would've got bored much faster reading effectively the same posts about startups over and over again. The wider scope has probably helped to keep the site fresh for me, at the cost of somewhat lower signal/noise.