I've been in a guild for quite a while and imho it would be more benificial for the game to have some kind of guild warehouse or guild bank where players can exchange goods inside the guild...
This will allow players to be more active in their guilds, and new guildmembers to get the help with resources they need while building up their island.
Maybe there should be a system inside so it keeps track on which member did what actions (add, take etc...) and later the warehouse could be used to enable more elaborate guild quests and/or guild buildings.
It's probably not the newest idea, and might already be proposed, but still.. this is another call for it then