Maybe some procedurally generated surface biomes such as factories or small industrial cities(including set armor and weapons + set fancy equips)... Just a thought.
EDIT: I believe that the junk jack universe is complete anyways
I see you are doing that one thing at that one place at this one time.
I absolutely love all of these suggestions. Little randomly generated structures would be fantastic. With the steampunk theme, perhaps they could introduce some sort of elevator or teleporting device? A couple things ive personally always wanted to see are: some sort of chest with the same mechanics as an "ender chest" from minecraft. They could call it an "aether chest" or something. Also, it would be cool if you could get a pet that emitted a light value. It would be hoppin around and be all glowing bright! It could be some sort of little fairy. Or maybe a little r2d2 type of robot with a light bulb on its head to go with the steampunk theme. Lastly, id like to be able to play with the camera zoomed out just a little bit. Like on iphone when you hit the map button and it zooms out that first little bit. That'd be perfect.