Re 4), above — could do with excluding the groups I’m in, too.
So, the tabs would be: The Hub, Groups I’m In (only) and Groups I’m Not In (no hub, no ones I’m in).
Not sure there’s a need for “Groups I made” — muddies the usuability waters again, I feel, but am happy to be corrected by people who use it all the time!
And, again, I’d collapse the Hub down into a single, filterable non-group — ie, users have to receive access to it, no opting out!
Quite probably, these two changes, together with a change to the formatting of the emails (including a “reply” button at the bottom of the HTML formatted email) would probably make TalkPhysics more attractive to me than continuing with PTNC as my primary communication method. Soooo close!