How about a skill tree for the mayor. You click on your avatar in the top left corner and a skill tree comes up. This tree has skills that enhance your island life. Potential skills I have thought up thus far:
Buffmaster: (Top Tier Skill - 1 codex) Increases the duration of all buffs dropped on home island by 1.5x (so same as if friend drops; only works on buffs that have the friend drop bonus)
Aunt Irma's Apprentice: (Top Tier Skill - 1 codex) Increases Potency of all buffs dropped on home Island by 1.5x (so 100% becomes 150%, 200% becomes 300% and so on; does not work on premium tokens, barracks buffs or rainbow snows)
Play it Again: 10% chance map gets refunded after use (have 10 woodcutters, use 1 and reduces to 9, skill activates and you get the map back to make 10 but still have the adventure active)
Double Time: Settlers travel to/from storehouses 25% / 50% / 100% faster
Long Road Home: Troops not assigned to a general at the end of an adventure take 1 hour / 30 minutes / 15 minutes to return home
Like Sardines: Total population Cap increases by 5% / 10% / 15%
Pile it Up: Total storage cap increases by 5% / 10% / 15%
Pull Together: Decreases building upgrade times by 10% / 25% / 50%
Tighten that Belt: Decreases building upgrade costs by 10% / 25% / 50% - does not affect token costs
Keen Eyes: Collectibles appear highlighted for 15 seconds / 30 seconds / 1 minute when first appearing
Scavenger: Total collectibles spawned increases by 1 / 3 / 5 - does not affect event collectibles
Look Harder: Number of collectibles picked up increase by 1 / 2 / 3 (so instead of getting 2 banners you would get up to 5 - does not affect event collectibles)