Right now, the primary thing that causes something to succeed on reddit is the rate of upvotes. Anything that takes time to upvote will be less likely to succeed, because it will receive its initial upvotes at a lower rate. (It takes at least an hour to upvote a great new yorker article vs. something that will be voted based on the title alone or a 1 second click.)
To fix this, you need to track click -> upvote interval and correct for this.
This is the main reason why subreddit quality goes down with size. Only the extreme head of the "upvote rate" distribution has an opportunity to succeed when the subreddit is large, so the "upvote rate" drowns out the "upvote ratio" as a factor.
I guess my commentary would be that there's a lot of places for people to be pleasant to each other and to discuss their shared interests - be it enthusiasts forums or facebook. The risk is being the place people go to be abusive and share their degradation of other people, and it's difficult to just take the rough with the smooth in that respect, when other communities are held to account for that sort of behaviour.
The issue is the people, not with Reddit.
That is always true, in fact I'd go as far as to formulate Waldens Law, "if the issue is either people or X, it's people" ;).
It's not like all forum-software-innovation stopped in June 2005 when the 2 of us launched reddit to the world.
The hard part is going to be quantifying "quality of submissions" in a scalable way. We thought a lot about this and while it's not perfect, the vast majority of content on reddit across those half million communities is indeed good.
It's a fascinating problem that I hope someone can solve -- improve on Steve's hotness algorithm!