With all the new players I would like to grow my tribe, so after discussing it a bit I was thinking we could use a tribe rank between member and elder, along with a new door which that rank and above could use. This along with changes like default personal towers should make it more viable to invite people without spending a few months getting past your trust issues =p
This is currently a good idea, unless your base design is very well made with access to shared resources being controlled, making new people work together is very difficult.
There is a terrible issue with people making several alts to infiltrate guilds and steal or rat out secrets. It makes growing your guild a game of two steps ahead and 3 steps back whenever something wrong happens.