In my opinion, I think guilds would be cool if they had restricted access. Meaning one or two people decided whether a person should be allowed in, or the whole group would vote.
It should be made that 'resources' or advantages are shared between the group, so in a self preservation sense it would work to keep it small, however when more people join the whole pool of resources becomes larger - helping the element, and the guild more.
Obviously this would go down after an optimum number, so the guild doesn't just accept anyone who applies just to give everyone an advantage. After a certain number of people join (the optimum point - probably based off the amount of people actively playing WoE, this would rise over time) the amount starts making it unwise to let people enter the guilds. (When the game gets larger, the optimum number would raise, and therefore guilds would want to recruit/accept again)
I think this would make it better because it allows the team to think about who would be the best, and really makes you think about when and who to allow to accept, since you want both active and skilled people (In theory, I'm not too sure about the bonuses and responsibilities of the guilds).
I don't want to detract from the brilliance of this post, so I'm going to keep my mediocre names in the spoiler.
ShadowCasters (If you think about it it's much less impressive than it sounds, so it suits darkness perfectly
Breath of the Sky
Wave Runners
The Diamond Hammer
