My personal problem with HN is all the different links with titles that half of the time do not really cover the contents. So I spend to much time opening links and wait valuable ;-) seconds just to discover it was unnecessary. Or skip links which might have been very interesting.
So to speed things up, my ideal reader shows not only the link, but also at the same time a screenshot of the page behind it and preferably even (part) of the actual text. That way I can judge really quickly if its worth opening and reading the page.
I would certainly spend money on that one.