Another thought I had about purges is reflected in an old suggestion of mine – Purge Suggestion -- ability to trigger purges – the basics of it is to implement a new building structure/crafting station that a player can put one or more of the keystone pieces (such as the staff, scourgestone, etc) and it will instantly bait/trigger the purge into action to attack your base in an attempt to claim the keystone piece.
This could complement (work alongside) the current purge system – rather than having to wait for the purge meter to be full, my suggestion could be used to trigger a purge regardless of where the purge meter is at.
This way, clans that want to be purged can be purged at their pleasure, and those that don’t want to be purged can wait it out for the dice roll after the purge meter is full.