My ideal: slower, more real time, full maps based on actual locations, replay specific naval battles. Multiplayer (maybe it is?), realistic fog of war. I could go on
Edit: a few more. Sail trim is clunky and seems unresponsive or unclear how it maps to physics. Would be better to have trim on one side and steering on the other. Also to turn off tacking with tap. Steering too sensitive. The battles are great. (All on mobile)