How long before web designers start complaining about reddit the way they complain about craigslist's design?
In Craigslist case, there are clearly better ways to browse housing spots than in a list of links with non-standardized location information in the linktext. In Reddit and HN, part of the joy is serendipity...you don't need to aggregate the content behind each link at once...because of the voting system, you don't worry that clicking on the top link will be a waste of time. That's not the case with CL's chronologically ordered list.
Reddit has made some concessions with allowing thumbnails of image-based posts to show up. Otherwise, its minimalistic approach serves a real usability purpose and is not simply the result of stagnation.
Picc.it is tuned to sharing pictures with people you don't know, but share your interests.
Think of it as the difference between glomping onto a pre-existing community (e.g. Facebook friends), and creating a new one (e.g. Reddit).