Things that will drastically improve gameplay (for me anyways) and some things I've noticed while playing. HP bar should also display your HP in numerical form. This also applies to Tech bar. Monsters do way too much knock-back, 60% of deaths are me falling from heights and dying from getting kicked like a football. I know this has been suggested somewhere but I insist that there needs to be an inventory and storage sorting button where it stacks all items and re-arranges in order. Toggle option for being able to attack NPCs such as villagers. I've accidentally killed many villages while trying to buy from merchants / sorting inventory etc . Toggle option to open chests or break/place blocks within someones ship in multiplayer, griefing is killing multiplayer, I want to meet new people and play but unfortunately a lot of them will steal your things or wreck your ship. Save favorite planets in a list to revisit faster rather than writing down co-ordinations. Keep windows in the same position placed instead of resetting position to the middle of the screen every time I open inventory its in my face, i want it in the bottom-right tidy and away from my face so i can see what's in front of me. Travelling to planets within the same sector takes the same time as travelling to far away planets within other sectors, please make it shorter and decrease the cost of fuel since its a nearby location. Torches take 1 coal per torch, make it 2 or 3 torches out of 1 coal since coal is needed for steel and other things i don't want to waste it on making torches. Add Mining helmet with a torchlight attached. This item was available in Terraria but my God did it help, it was worth the money since you don't need torches and it would save coal as well as time placing them in blocks. While holding a source of light such as torch or oil lantern it should act as if its placed on a block and therefore it should brighten the surroundings. Just thought i'd let out what i was thinking I know there's much more but ill keep it sweet and short since the rest have probably been mentioned or are being worked as we speak.
I also think as just a small thing open inventory when using a 3D printer so it is easier to add things too it.