^This would be nice.
Better Lighting:
I thought they could add more light fixtures, like have crafting recipes for torches that can put them in little light holders you can mount to walls, or maybe a candelabra or sorts. Also could make a mining hat or something to where when you are wearing it as a helmet it has the effect quoted above but without having to hold the item (similar to in Terraria). Flat lighting would also be nice, like a carpet that emits light, preferably vertical though (unlike carpet).
Furniture:
More furniture! I want where you could place a couch seat and it would be one seat, if you place 2 next to each other it becomes a couch (similar to how chests combine) and the player should be able to sit in the chair like how they can lay in a bed. I think this idea would be kind of fun. Other types of furniture could be added as well, like tables and wooden chairs.
More Dyeing:
I would love to be able to dye all armor instead of only leather. Also, I would love to be able to change the color of a bed by clicking on it with a dye in hand. If the couches thing would be implemented, I would want to be able to change the color of that in the same manner.
More Paintings!
Something I have wanted for a very long time, since I first used all of the paintings. More paintings would be awesome, especially if there was some way of crafting/choosing which painting you want it to be (even if that change is permanent). Also, being able to upload your own images to paintings seen in-game would be amazing!
I could think of a bunch more stuff if I had more time, but for now I'll stick with this list.
