[Merriweather]

That and that when a group leader has no avatar, no members WITH avatars show properly as well as the missing post icons and titles.

I think those are the last "broken" things I am aware of.

Non broken things would be:

(1) Something to allow admin to see users in groups (and remove them) who shouldn't have access (you mentioned a new release would check user permissions in addition to whether they are a member -- this is very important)
(2) View post history when replying (like forums)
(3) Subscribe to groups somehow? (I, personally, don't care about this, but my members sure seem to be in a tizzy without it). Perhaps even just a temp fix of showing "Posts since last visit" in the User CP under the group name or something... ??