Well Roblox's suckiness (from what I can tell) probably stems from the fact the game is marketed at actual children (so the community is really difficult to put up with), and the fact it's been heavily pushed towards an ethically-questionable monetization scheme.
As for Minecraft, well, that's kinda been pushed that way, thanks to Microsoft probably pushing down all sorts of nonsense antifeatures on the non-Java versions, and attempting to push people away from said version as well.
Both games can still be enjoyed, sure (Minecraft in particular, with the immense amount of mods out there), but They're Not What They Used To Be.
On topic:
A game where you run a space shipyard - taking orders (from all kinds of clients both human and alien), constructing the ships, managing your staff and resources (raw materials + premade ship components) and eventually expanding the facility to allow for building more, and bigger, ships.
(But never actually flying them or fighting because that's not what the thing is supposed to be about.)
I have an ever-so-slightly more expansive ""design document"" (If you dare call it that) on this, and hope to maybe, just maybe, get a prototype going at some point. But that never goes well with me, so who the hell knows...