Some quality of life features for groups.
1) When inviting a user, a confirmation should happen.
2) The logic for public/private/secret isn't quite right. Fix it.
3) Feature / Pin a group to the top of the listing
4) Share threads to groups / groups to threads with high quality embed
5) Assign moderators with customisable permissions
6) Auto replies to threads..?
7) Customisable sidebar for each group for the group admin, with latest, trending, etc widgets available.