I think it would be nice if it would be possible to capture enemy starbases, even starships, mining outposts and possible other player owned objects in outer space as is possible with planets. Maybe by having some kind of special commando module or something like that. And then there should be a way to defend yourself from that.
The starbases would be the best example, there is no need to destroy it if you could repurpose it for yourself. Some modules could be destroyed during battle and starbase could be self-destructed before capture, possibilities are numerous.
To make, for example, capturing starbases work they maybe would have to be made more expensive to build to have a reason to go through the hassle of capturing one.