I agree completely with #1, although I disagree with most people that HN is a pleasant design. It's ugly as sin, as is Reddit, but they are link sharing sites,

I agree completely with #1, although I disagree with most people that HN is a pleasant design. It's ugly as sin, as is Reddit, but they are link sharing sites, so it doesn't really matter what they look like so long as they make it easy to share links. People have grown used to the way it looks (as have I, despite hating the way it looks) so deviating from that is always met with resistance. If this were my plugin, I would not alter the look and feel of the site at all (much like the Reddit Enhancement Suite does not) but I would provide the ability to toggle the current design alterations on for those who want a more pleasant experience. That would increase your adoption rate, I'm sure.