Sounds great! I've been thinking about making something similar now for a while.

If you don't mind me sharing ideas that I would love to have in such an extension:

- Changing the UI of the comment actions to make them easier to use. Using HN mostly on a phone, I keep hitting downvote when I mean to do the opposite. Similar with the collapse action.

- Keep a local list of users that get their comment subtrees stripped out. Some people are argumentative by nature and not in good faith. It's best to ignore them (easier when you don't see their comments).

- Hide new accounts by default (perhaps auto collapsed).