Except this design isn't better; it makes scanning many headlines more difficult and the typeface is harder to read. Anyone who reads much on the web is used to sans-serif, and it is, in face generally more legible because on low resolution devices (ie. screens), the larger counters are easier on the eyes.
White space for the sake of white space isn't an improvement, and doesn't always help consumption of dense amounts of information. Consider a book -- would you arbitrarily increase the line spacing to double spaced? No, because it doesn't actually help.
The part of HN that matters is the headlines, and scanning them looking for things that interest you. Good design isn't about being pretty, its about being pretty AND useful -- this design does not succeed at that second test.