When expedition ships set sail, wouldn't it be cool if they could discover new technology to improve efficiency and quality?
Let me give you a few examples of what technologies that I think would be interesting to discover and suggestions to what effect they could have:
Plow (combine that with donkey? to improve efficiency). Compost (or other fertilizer techniques, perhaps manure from domesticated animals for faster growing and longer lasting crop yield). Improved fences around farms (stone fences? They could have the effect of reducing damage from weather disaster and raiders), improved tool designs (on schytes, rakes, spades etc to increase duration or efficiency).
Improved clothes for work (giving tailors ability to make gloves, boots, hat, scarf etc, and also clothes to suit the different seasons, warm clothing for winter and cooler clothing for summer for increased happiness or productivity). Foregin knowledge (an expedition could see some new ways of doing things, and combining that with what they already know, that could serve the effect of new rescource gathering techniques and increase resource gathering productivity or tool duration). Skis or sled (to increase movement during winter). Portable lantern (so they can work a little longer before night falls).
Improved isolation (to consume less firewood during winter). Decorations (to increase happiness). Basement (that villagers can use as personal storage for food and firewood in order to alleviate the barns). Theater (to increase happiness).
Carriage (to transport larger quantities of a resource to storage, and to usage). Riverways (utilize a river to transport timber and other materials).
As a summary I'd just like to say that it's only ment as an elaboration to the exploration system you already got. I've ran out of things to discover, and would like some more.