Looking through the Talent Trees, there is a distinct lack of talents that benefit the guild. The only one I note is the Bounty trophy Bonus talent. There are other potential talents for guild focused players, for example:
-Investment tick cost reduction
-Increased Guild Help time reduction (i.e. how much time you give to guildmates when you Help their Upgrades/expansions)
-Increased number of ticks % bonus in investments
-Chance to give guild request without cost to you
-Increased value of Guild Event points for just the guild total (personal points unaffected)
-extra guild member slot available (perhaps not to exceed max, or perhaps permitting a double sized guild)
-increased Friendship level
-Increased benefit given for a friendship act (more energy for cleaning shop, more time reduction, etc)
-Increase friendship xp for friendship acts
-bonus to renown points earned
This could potentially be done as a 4th tree (pulling trophy bonus into it), or be added to existing trees.