From these options its winds and currents. But overall I think we need technologies. All other features are nice too, but increase of complexity is the main way to increase value of the game.
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The reason I don't add technologies as an optional feature is that those are dependent on the main features that are already part of the roadmap. Also, all of the content-related features are going to be mod based. So I expect most of that stuff to be added by modders while I work on essential simulation framework elements.