It impossible to know your when your guildies join your guild (except you ask them). And it is hard to know who is leaving your guild. So my suggestion is:
1. Make a notification when they started join the guild. Same like Three Rings do to knight last play time/date.
2. Tell us who is leaving the guild by using SK mail.
Well I think that will help me and other user a lot.
By the way, if this has been discuss.. please notice me. So I will not make a same mistake again :p
Snort snort.