Did FFH2 have a system of Items being carried by Units?
They did it in a totally different way. A magic item is a unit. If you have another unit on that plot, it can do a command to pick up the item. If it does, the item disappears and the unit gains a promotion. If it drops the item (command available if it has the promotion), then the promotion is lost and a new item unit is generated.
There are 3 ship promotions, which can be selected in port. They give +1 power, movement and cargo respectively and selecting one will disable the two others. You can switch in cities.
(at least that's how I remember it)
I am not sure about the implementation of some of the more command items that units could carry. Like for the examples Night gave, the Sea Rations and Balista would be a good addition but more minuscule items like crows nest or body armor would seem to work best as a Empire wide Tech addition.
Those were examples on what the concept can handle. Figuring out actual addons and how to balance those might take more than the 2-3 minutes I spend on the examples.
As for stuff like crow's nest being empire wide.... I kind of like the concept of having too few cargo slots for what you want and hence have to decide tradeoffs when outfitting your ships. Maybe it isn't totally realistic that a crow's nest takes up a cargo slot, but I think it will work well from a gameplay point of view.
Considering that all they do is to give promotions, we can let addons give promotions, which can be gained in some other way too. Say we can build crow's nest addons at turn 50, but at turn 200 we gain a civic (tech), which gives a free crow's nest promotion to all ships or certain ship classes. We also have the option of allowing the promotion though experience, which will make the ship keep the promotion even if the addon is put back in the city. We can also limit the experience promotion to certain ships while more ships can use the addon etc. The feature design allows an extreme degree of freedom when setting up in XML.
If I read the replies right, we all agree on the DLL part of this feature. However the XML part is more vague. We need to figure out what specific addons we want and their effects.
AI is an entirely different problem. Not sure what to do about that one yet.
I added a ticket for this idea:
https://sourceforge.net/p/colonizationmodcollection/sourcetickets/1/
We should add tickets for all feature ideas as well as bugs. That way we have a searchable list and we have less risk of forgetting good ideas. As it isn't meant to run in parallel to the forum, I just linked to this thread for details. I assigned myself as owner of the ticket meaning I will be the one coding it (once I get my compiler up and running again).
It would be nice if people would add ideas and bugs to SF.