With the recent change to allow swiping for actions this checks almost every box I have for general usability. Just two things come to mind:

1. It would be nice to be able to tap a comment to collapse and hold to show menu when swipes are enabled so it's a bit faster to browse comments.
2. The ability to pop out an image (that can be swiped away, ideally) would be nice since clicking an image halfway down the page often leads to having to scroll down to see the whole thing.

Relatively minor things and doesn't break the experience at all, but would help usability just a touch.