My suggestions, which may have already been suggested before are:
~ Guild Message board (In Guild House) – guild discussions, policies, rules, Schedules can be posted here.
~Guild Storage/Banking- to store resources for funding future events or stockpiling items and materials for guild members.
~Mass guild mailing system - CC/Bcc would be nice. Guild members should be able to contact multiple members via mail or anyone in game like this as a matter of fact.