We just added a new function that you can find in your guild configuration page.
It allows you to automatically remove members (& postulants) that haven't played the game in the past X days (X= 100 or 31).
Could staff add a function that tells you who in your guild has not played for 31 days too. This way, we could alert those players first, and then, after a couple days if they are still inactive, we could then give them the boot.
Also, a similar function that tells you what friends are inactive would be great too.