Consider adding a Tiny Grid size
My experience building a working drum synth shows me that fully functional devices can exist as player made content in the game. The problem is, everything is giant.
Introducing a Tiny block size, let's say 5cm, and a way to handle Tiny Grid objects with hands, could allow for so much — custom built weapons, electronic devices, just small normal buttons, switches and control boards, furniture, decorative objects, tiny helper robots, and myriad tiny pipes running all over the place. I mean it'd open up a whole other layer to the game.
I realize this is easier said than done, but please at least think about it. :)