In the words of Steve Jobs: "That is really ugly, and you're fired". It has that failed Web 3.0 look. More rounded corners, excessive margin, but less content per page. One commenter pointed out its easier on mobile, but that can be resolved with the existing style.
Me too. I can't stand unnecessary whitespace, the current size of HN is readable enough as it is on the desktop, the condensed content is a feature, all HN really needs (IMO) is a better theme for mobile and collapsible comment threads.
fwiw I'm not a designer but I found it very hard to read because of all of the excess spacing. I had to read one article header at a time instead of just scanning my eyes.
Please, think of the children.