We unfortunately can’t make long press the collapse post gesture, since that is already taken by the system context menu behavior. We can, however, add an option to disable tap-to-collapse, since we already have the alternative of swiping very far to the left to collapse a comment implemented.
Swipe actions on expanded posts should be feasible, but I’m not going to promise it until I’ve reviewed our other planned features and verified that there aren’t other uses for that gesture under discussion.