We’ve started to implement Planet Secession. Affected empires have their planets secede randomly, which become re-explorable.
What causes a planet to secede?
The only factor for the moment is an optional per-galaxy planet cap, and right now Manthano 2 is the only galaxy where this is happening. While this feature was added specifically as a means to help us manage Manthano (instead of having to delete entire empires), we can now also use this as an option for any galaxy.
For example, we can now run new game types with low planet caps where huge size leads are impossible, which would reduce economic disparity. Such games would shift the competition more towards active military conflict than sitting on huge banks.
See the idea thread for more ideas for this feature going forward.
For questions and feedback on its existing use, feel free to reply here.