Alright, I've done a quick search so sorry if I have missed a similar or exact suggestion.
Having dipped my toes into PVP, Crafting and trading, I've been thinking about what could improve the current system in this play run economy.
Ultimately with how harbors and player buildings work at the moment, most people are using daily teleports to move a fair amount of resources to their crafting hubs with relative amounts of safety. Most suggestions have at removing the ability to teleport with items in hulls and some extremes have pointed at removing the teleport feature completely, but lets face it, it's removal would be a big pain in the ass. With a player run economy the second issue with not being able to teleport goods safely, would be that smaller pop nations could ultimately be starved completely out of certain resources if they were heavily blockaded and harassed, right up to the point where they would no longer be able to properly fight back (More of an extreme event).
Okay enough be blabbering on about next to nothing, lets get to what I have in mind.
Other than different ports producing resources, make a good amount of ports (Non home ports) have some sort of built in specialty as well. Obviously this is just bare bones but lets take for example a Port which has a sawmill or something along those lines, make it so that any wood working done while inside this town will only cost half the labor hours (Or a small % Decrease if you will). You might have a Port which has an industrial furnace, the bonus which it provides might be that you might be able to make 2 bars of metal per coal or something along those lines.
Okay, so now why would all this benefit the game?
Well for traders/crafters. This would provide the possibility of saving some labor hours or using less mats while crafting, however at the cost of needing to transport the right materials to the town, during which you open yourself up to being attacked. This adds an element of risk and reward.
And for Pirates (Both faction and enemy faction)?
Well opportunity is opened up for rewarding raiding, finding players with actually full cargo holds will be a little less hit and miss. As a whole it would also make attacking certain opposing nation ports a little more tactical without completely removing a nations ability to produce goods. I suppose in all it would make things a little more dynamic.
Anyway this is simply the skeleton of the idea I'm thinking of, once again apologies if this has already been suggested. Fell free to expand, flame or compliment below.