I'd like to make a space opera RTS game that features Reasonably Sized Military Spaceships.
I want the characters to board a mighty beast of a ship, like one hundred metres long, which is a lot (frigate-sized, more or less), and then go visit some very minor celestial body and feel small again (e.g. Phobos, a tiny moon around Mars, is some 20km across, basically space's equivalent of an island)