Furniture and greenhouse
This game is brilliant, but it's missing some key items if you want a realistic ship. A few creators have put similar items in the workshop, but it's not enough. I refer to furniture for crew quarters or for the bridge of a ship. Beds, chairs, tables, desks, kitchen and mess hall item, appliances for cooking, food storage, showers, toilets, sinks and even exercise equipment. These items would be essential on a ship. As well, the ability to make an area on a ship with trees and grass. Again, a large ship would have this. But, you could take it a step further and introduce farming, with the ability to grow food on a ship. As well, the plants could contribute to the levels of oxygen, providing air to breathe, a recreational area for the crew to maintain their psychological well being and finally, it feeds the crew.
Items like I described are what the game lacks and would add more realism. You could build a luxury space yacht, like a hotel, with first class rooms for guests and a park area with a glass roof for their recreational activities. Or, a warship, with tiny crew quarters. Stackable beds could make bunks for crew. Or, a huge double bed for the captain or rich guests.