-Explore stations populated by tusk (without diving suit) or people that went rogue, that would be a reason to carry bullet vest and helmet on this expeditions.
-Getting unique items for completing quest or find them, like diving suit with scooter build in (consumes oxygen and battery), automatic arpon gun, etc.
-Fight rogue submarines (board them or be board), they could go away after down your submarine so u could repair and then counter attack or just leave.
-Small coil gun for shuttles
-Long, medium, short campaign and maybe difficult options
-Be able to take more than one mission per trip (this will make MP more interesting)
-Make Npcs make more types of comments when ship is under attack, health condition, fuel roods available in storage, ammo count on coil gun when using it, % of welding tank etc.
-Npcs should change their headset battery and oxygen tank prioritizing doing when not in combat or stress situation from rechargers so there is a cycle empty and full.
-Assistant Npc could be in charge of recharging oxygen tanks and batteries as well putting diving suits in place, recycle empty fuel roods.
-Security NPC has the ability to cycle between the guns according to the enemy position if there is someone handling the radar, also bee able to see in the submarine image of the radar where are your guns and if there is someone using it.
-Stacks of 5 for crafting materials as well for fabricator output, as well in the output of the fabricator.
-Be able to queue crafting items up to 5 to reduce the micromanagement especially in single player
-Be able to move crafting menus had 2 cabinets linked to the fabricator but menus goes to weird places on the screen. Be able to link cabinet to the medicine fabricator as well.
-Station sell limited amount of items and be able to sell
-Only one box tool can be carried on inventory
-To harvest plants u need a knife
-More models of items more types of cabinets, pumps, etc.
-Be able to create your captain still random skills
-More traits and more weight on the skills of every crew member that could impact the game.

Hope something of this could be useful. Looking forward for the next updates cheers.