Earlier quoted context omitted.
Threading could be clearer. Less data would need to be loaded on each page load. I can imagine that a lightweight SPA to handle the a few standard views (e.g. listItems, itemDetails, profile, changePassword, submit) would cut down data transfer by a significant margin (20-30%, maybe more). The UI could also be much better on mobile, and we could give users the option to cache certain pieces of content offline.
What you’re suggesting is heresy on HN. It’s true, a little bit of interactivity, fonts/padding/spacing would improve HN. To this day my thumb covers both the upvote and down vote button.
A lot of people think that moving to an SPA would mean killing both those aspects. But the truth is, you CAN have an SPA that is both lightweight and fast - the developer just needs to know what they're doing.