Hi, I’m on the Membership Board.
We did have a discussion about this very issue, I can’t remember if it was internally or publicly. But, one thing that I want to make clear is that membership is not there for life, you have to renew it, unless of course you get it indirectly (and those teams make you renew the membership there as well).
I would disagree that a “check in” is needed. If an Ubuntu Member is very obviously active and responsive, we shouldn’t have to make them jump through hoops to confirm that yes, they still contribute to Ubuntu. That would, in my personal opinion, become annoying and tedious. Unlike e.g. Debian, there is no concrete way to tell if a person is still active; it varies. So you have to analyze that. Plus, with members being prompted to renew every two years, they should take a look at what they do in Ubuntu, even if for just a split second, and decide if they want to renew that or not. They should have the opportunity, as responsible contributors, to decide whether or not they want to keep contributing, and shouldn’t have to ask a board to re-approve them. After all, they became Ubuntu Members in the first place because of their significant and sustained contributions to Ubuntu. They shouldn’t have to put in more effort to prove something that was once apparent. As long as they renew their membership, Ubuntu is still at least a thought in their mind. But, that is my opinion. 
On the other hand, we did decide as the Membership Board (well, I remember hearing no objections) that in order to get your Ubuntu membership reactivated after a bit of time, there would be a short list of questions, with the focus of “Why did you come back, and what now?” but the criteria for that hasn’t been laid out, and this hasn’t been formally decided on yet. I will personally seek formal quorum on this and draft some criteria, as soon as I can.
Let me respond to a few specific points here:
My proposal is to first disable auto-renewal of Ubuntu membership in launchpad, If someone cannot even bother to renew their membership there is no point in them being one but there is more, Ubuntu membership renewal should be extended to every two years (or one ?) with a formal meeting where you have to highligh that you still care about Ubuntu and helping to make it better in any way (criteria: TBD).
See above about why I think this is the wrong approach. It can and will get tedious quickly, and it will put a huge burden on the Membership Board to confirm that already active people are still active. If people want to do yearly reflections, that’s up to them.
For the expired members we could just create a ~ubuntumembers-alumni.
This is called the “Former members” section of Members : “Ubuntu Members” team 
What we need, I think, are more spaces to make potential new members feel welcome, and to make old members return*. I don’t see much value on tagging people as ex-members.
For the record, we have seen much less applications for Ubuntu Membership lately. I can see this being for a few reasons, but I think it’s outside the scope of this particular discussion to figure that out.
