There is no way to format your text, even stuff that's available since MS Word 1.0, such as bold or italic. Even science papers have formatting so I don't buy the "overuse of styles" BS.
There is no way to have avatars or some other ways to distinguish users (or mods!) to make this place feel more like a community in real life. I've gotten used to it but it still sucks.
The contrast is super low.
HN is an MVP for a super minimalist forum that wouldn't fly for any other kind of community except for the intersection between hackers and wannabe entrepreneurs.