it might be a good idea to add more mini games that can be played only once every 24 hours much like the gong of wonder.(gives you something proactive to do while waiting for buildings to be build or tech points to be made)

adding a mine or something similar to collect recourses to be able to build in stead of making the build time really long.(make villagers collect a certain amount of recourses before being able to construct the building)

also different resources could be collected for more stews, hunting for special seasoning to make extra special stew.

also making more tech options available as you progress instead of the 6 basic options we have now you could gain more options as you progress.
for instance if you gain a certain amount of tech lvls a different more specific technology option will come available
herbalism---->medicine
with herbalism you could become able to use more of the plants found in the region making them more useful that just training medical skill and with medicine you could use the herbs to make medicines for certain illnesses so they wont return to the island.

also instead of the one map you could make more area's to be played open via certain puzzles the villagers could have one map where the village would be with the basic food recourse but later in the game you would have to make a farm outside of the village that way you have more places to hide certain plants or items needed for the puzzles:

[sea] [forest] [waterfall]

[sea] [village] [river]

[mountain] [ruins] [lake]

just an example each word would represent a small map in which certain mini games or actions could be done by your villagers.
the advantage from this would be simply more room for structures in your village as well as more possibilities technology and game play wise.

i know a lot of these things are probably not even possible to put in the game.
these are just my 2 cents i hope they will help