If you really wanted to make the site more like it was, you could look at the voting history of people here at some distant time in the past and find other members whose votes highly correlate with the old timers. Some people just quietly upvote, so they don't have much karma. If you want the upvoting to be more like it used to be, award people who vote similarly like how older users used to vote.
It would help take care of the effect where older uses leave due to changing interests etc.
Note: I don't actually think it's a good idea. I think just figuring out _what_ you want exactly, in vaguely quantifiable role, is sort of a hard problem. I suspect a lot of people have different 'golden ages' in mind when they think of HN.
When I came here originally it was pretty startup heavy, which was sort of remote from what I was up to at the time. I liked it when it got a little away from startup business related stuff (my perception) and toward more generic technical issues. My point is even if everyone agreed that ait has gone done hill (an open question), not everyone might agree on what it should be like. It's not a democracy of course, but even as an individual for my own preferences that seems as hard as the technology issues.