I can tell you one issue I observe as someone living in a different timezone. HN ranking highly depends on timing. As a consequence during hours the US is asleep my impression (I have not investigated this thoroughly) is that front page stories are dominated by old stories and new submissions don't make enough votes to get to the front page. Then once the US wakes, New stories get enough votes and make it to the front page. This leads to biases in the news, which I find unfortunate, because I believe everyone would benefit from news being geographically (for lack of a better word) broader.
I certainly welcome someone playing with different algorithms to see how they affect ranking.
If you're interested in investigating timing effects: We collected a dataset last year where we took a snapshot of the newest 1500 stories on HN every minute for several months which should contain the information required. Feel free to play around with it and get in touch with us if you find something interesting!
I certainly welcome someone playing with different algorithms to see how they affect ranking.