There needs to be more/better guild perks for members, more then 1 at the very high end of a guild. There would be more incentives to join a guild and work together. Increase ones own power through the guild while helping it out at the same time. There are a lot of people that are not in guilds and I don't think its because they don't want to be, I think it's because guilds really don't offer them anything. I think making guilds more like this would make a lot more them/get a lot more people in them/making people work together more/making them play more/longer.
+1 extra unit to ones own army and the higher the guild the higher the unit is
(level-1)Protector--->--Preserver(level-2)-->---->?
will add more
Thanks
-stach