Hello Izzi. I'll resume the idea in the following points:
About campaign:
Adding some region specialties
Adding historical places, specially historical missions or places were foreings could be placed
No more new regions are intended
About maps:
I picked Nagashima historical map and the city town i made and totally revamped them. They are now more or less cpu and AI friendly. The worst performance in terms of AI is when the AI defend the farm town.
Relate the maps to the campaign. For that i need an excel with the location of every settlement (name related) in the map and do the script.. Really annoying task
About historycal maps, i need to do some improvements to them, it would take me some time but i think i might have found a way to make the Ai work properly with them.. Those maps are so large that the pc never worked good enought.
Adding more farms and ports maps is possible.. It depends on how you split the levels .. For fots you have 5 lvls 7 variants .. If you give farms and ports only 1 lvl then you could use lvl 1 and have like 4 type of farms and 3 types of ports .. Trouble is that making maps is super time consuming, and if you do not limit very well what are you doing you might end having an unplayable map for the AI.
Here you have the link for the 2 maps
DOWNLOAD
Note: I may improve a bit the farm one in the future.