I am a long time fan of SE, literally you build the game I have been dreaming of forever. My best idea for SE is the need to force multiplayer interaction. I love to build non the less, but wheres the fun in everyone just mining and stockpiling, building, repeat and maybe seeing someone randomly on the server here and there. I get there is a lot of mods out there to increase those chances. But really this game is almost too heavily dependent on mods. At least in the servers for the most part.
I dont think it would be hard to impliment really. Just add components needed that cannot be built. Have area's that can be attacked, looted, discovered, really the possibilities are limitless. Or have ore situated in certain areas like caves in planets.
I believe this would change the entire dynamic of the game. And a great reference on having great or a lot of interaction in multiplayer is the game RUST. It may be a bit of toxic gaming community but the interaction in Rust is very indepth. Have a bunch of your team play it for a while and see how much interaction is pushed with this game. It does have a building mechanic as well but nothing complex as SE.
The Other thought which also comes from the idea in the game RUST. Is have a block called the core. Where you or your faction need privileges on it to weld or grind or build blocks. This forces more action to the game in the affect that you need to blow open air lock doors or walls. NOT JUST GRIND THEM DOWN. Also its a way to try to infiltrate the ships we build instead of the weld the part half way down to hack it. If you got to the core. you would have access to the ships systems.
Please do read and consider this THANKS!!