I'd like to see civilians moving minerals around - mainly because I don't use mass drivers . . . ever. They just don't fit in with my conception. I want a massive merchant marine conducting trade all over explored space, and a navy tasked & honour-bound to defend it. As a result, I have hordes of freighters of all sizes and tech levels (I never obsolete designs, or scrap ancient 1-hold, Nuclear Thermal-engined tramps) following various 'cycle orders' trade routes to collect minerals from mining outposts and carry them to major colonies.
A hearty 'Yes, please!' to increasing civilian capabilities.
And instead of adding a mass driver subroutine to maintain X amount of mineral on planet, make it a more general ability. (For example, have the military ship "Load (TNE)" order ignore minimum stockpile setting, but "Load X (TNE) when available" order respect the decision to maintain a certain amount on planet.) I know I'm in a tiny (unique?) minority that doesn't use mass drivers, but I wanted to remind you that there's at least one of us around.