There have been a number of great suggestions already posted from others, and rather than co-op their threads for my own suggestions, I’m going to just link them in here. 
Before I start though, I do want to say how much I’ve enjoyed the game already, and what a great job I think Crate has done with it. And for the Devs, I understand that as an outsider looking in, it’s easy to refer to something as a simple, quick change when you’re not the one who has to make the changes. Every little change has a ripple effect into other already present systems, so I get that our suggestions, although simple seeming on the surface, may have much bigger challenges.
So my suggestion is to combine a number of the requested changes into a future DLC, much like what has been said previously about the possibility of bridges and water changes. I would suggest a DLC specifically targeting changes to the entertainment and spirituality systems in the game. This could include things like the suggestion by @Daniel_Soul about wine and wineries Wine and vineyard, the ideas from @Chris_Wells about a distillery Brewery upgrade/new building: Distillery and the great thoughts from @phoenixwind about a greater social system More social/cultural mechanics and lifestyle events/visuals in the town.
The reason I suggest this as a DLC is two fold. First, while I do believe it would be in keeping with what seems to be the vision Crate has for the game, it’s not necessarily for everyone. While no game can be all things to all people, the nice thing about a DLC is it allows those not interested to simply not add it. The second is simple scope. I understand that even little changes can cause much bigger effects than planned, and big changes can have massive repercussions. But, like was said with the use of bridges and water effects, while it may have a major impact on the game, it can be (with careful planning and testing, which Crate seems to be doing a very good job of) a very positive change.
The happiness system is very integral to the game. It impacts birth rates, immigration, labour, and even combat. As such, I think it could use a little TLC. Adding wineries, distilleries, and a more robust social system could do that. This could be much more than just a new food or drink for pubs or villagers, but also a whole expansion of the happiness system. Expanding on the tailor to be able to make tapestries (like the unit ones already planned for v0.9.2) and vestments for the people working at the shrines and temples could open the door to greater religious festivals, which in turn lead to increased leisure and happiness. Adding required foods, drinks, and other supplies for specific events can open up for players to choose to dive into the social and daily lives of the villagers more. Having an instrument maker, or making it a section of the furniture maker, can add even more requirements, and create additional options for festivals. Or, as was suggested previously, wandering minstrels, performers in pubs, park concerts, etc. And these in turn can not only make the settlement feel more lived in, but add more detail to the leisure and happiness stats.
I understand, these are huge changes being suggested. Something as simple on the surface as suggesting a winery can also make vinegar, and with that or alcohol from the distillery, additional preserves can be made (pickled eggs, fish, and even greens like sauerkraut) would totally change the current food supply dynamic. This is part of why I suggest it as a DLC for a later date. But in the same way that the upcoming combat and military changes are going to bring a whole new element to the game, a deeper dive into the leisure, spirituality, and happiness systems can create great new opportunities. And particularly for players who prefer passive mode to just enjoy the building and running of their settlement, this creates nuances and a deeper level that players can choose to take their game to.
I’m sure everyone has a list of little things they would like to see in game, and I could probably write pages of details of how I would like to see these systems I’m suggesting implemented. But I also understand the developers have their vision of the game, and this may not apply completely. That said, as a DLC, I think it has the potential to take the game to a much deeper level for those who are interested in adding those elements to their game play. And this is also by no means a complaint or knock on the game. I think this is already an amazing game, and I’ve certainly gotten my money’s worth out of it. And I’m looking forward to future updates. But, from what I’ve been seeing in the feedback and suggestions, I believe there is a want among players for these types of updates in the future.
Anyhow, thanks for reading, and enjoy the game folks.
Cheers