I'd like to be able to follow threads to get on-forum notifications about new replies to them. This should also allow users to say in their account settings that they want posting to a thread to automatically follow that same thread. (Maybe the latter's already implicit, though…?)

OpenRadar actually has at least initial support, per this PR - https://github.com/timburks/openradar/pull/44 to the project, for re-posted Feedback Assistant reports now.