I watched a bunch of previews by Nookrium and alike (didn’t play the game myself obviously), and got an idea about trading. The idea is as follows:
In addition to the current system, add global map with another settlements, Impression-style. Let the player build some sort of centralized commerce hub like Harbor or/and Bazaar (why not both for sea routs and ground routes) and establish trade routes. A trade route is managed Anno-style, and consists of one caravan/ship on our side. Also infrastruvture to build caravans/ships first, and dispatch armed guards with them, so it’s more of an investment and a mid-to-late game activity. Let the other settlements also establish trade routes with they player if they “feel” like the player have what they need in abundance and they have something to give in return.
Let the goods in different cities differ in prices too, depending on their own simulated “supply” and “demand”. If they lack something they need, they’re willing to pay more, and if they have an overabundance of something, they’re willing to part with it lightly. So the player can buy stuff at one place and sell it at a slightly higher price elsewhere. This will allow the player to create a bustling trade city! Invaluable for roleplaying.
To offset an inevitable buildup of wealth, there are two mechanics. First, as I mentioned, is making trade an investment by having a relatively high entry price. This way, the player will first have to feel confident in their economy and safety before committing to trade routes.
The second one is already in the game - raiders! Just make them scale even more if the player has disproportionate wealth compared to their production, so the player is forced to keep a hefty defence force at all times if they’re going Venice. Make the raiders attack from the sea as well as from the ground.
This will make the already the most heavyweight game in the niche just downright incredible IMO.
The third would be the changes in supply and demand - sell a lot of candles and the price will drop, import clay and stone and those will become more expensive. Leave a settlements demand for glass unsatisfied and another settlement might manage to increase their glass production, becoming fierce competitors if you do wish to start selling your glassware later on.
I had the exact same idea and wanted to make a post about it. Good thing i used the search function first.
I also would like to add that you could use resources (including people/guards) for expeditions to find new trading partners.
Building a caravan, with supplys and goods to trade.
Maybe have late game goods that are only available through trade.
Also using it as a resource dump by expanding and improving the trade network buy building up roads and station/guard housess along the way, reducing travel time and making it safer against raider attacks.