+1
Open access to: Island Creation, Custom Assets, Writing AI, Adding Scripted Features and Hooks (General Gameplay Scripting) -- borderline open source lol.
With Open Source Modding/Scripting:
Personally, would like to make AI improvements and behavior trees, adding more difficult island layouts (placement, size, and assets on the island.)
[For ex: AI control of its naval fleet is a bit under utilized. It gets 5-6 ships and they follow it around like pigeons with bread. The AI hides behind islands to shield itself from you - annoying but +1 for smart - yet that is easily defeated by throwing your whole fleet from one side and doing a pincer move.]
I would like to add more weapons/vehicles to the game, particularly sea vessels. I was modding in new ships until I realized that there wasn't access to defining their weapon assets.. which made me also believe that I can't add them to the spawn tables.
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I haven't yet attempted what Darloth is doing on the steam workshop with island generation, but I'm waiting to see what he eventually finds access to.
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In summary, I'm +1 requesting for near open source of game components (for expansion/modding.)