Having a few little things to improve the QOL would be top notch, most of the major bits you get from native apps you can get in progressive web apps (PWAs)
click to toggle deep comment threads
click to show actions on comments (moving the reply, boost, more into it's own section so you can see more comments on screen at once)
having the comments endlessly scroll instead of being paginated
It's a really nice site considering it's still early