when the dev gets asset editing, scenarios, and other modding functions working, you can probably mod units yourself then
Boats would be indeed an interesting addition to game. I’ll put that on the things-to-consider list when it’s time to work on improving the simulation modelling.
You should consider making Forts and Castles too!
Correct me if I’m wrong, but this game is based on the Sengoku period of japan (I believe there were multiple but you know what I mean)
Also I dont recall Japan having a particular Naval focus. idk if this game is supposed to be historically accurate, but it would be faster and easier to polish existing mechanics and possibly add buildings.