While I admit star wars games have veryyy mixed quality I would liken to shogun or total war but in space. This is one of my favorite RTS games out there for the following reasons; - real time fights in space and on land - environmental factors affecting battle in space and on land - development stage and fight stage are kept separate so you don't feel at a disadvantage to AI when you have to concentrate on the battle instead of micromanaging production where an AI does both - You can have a large galactic army without slowing down your computer because during development stage they are just icons with a number and its only when you are in battle that your limited, still with as much as you want as reinforcments when your numbers run low - very simple and quick development stage with a time boost option so you don't get bored waiting for enough units to produce
Obviously i'm not suggesting EXACTLY like this (especially as its a whole game in and of itself) but i'm thinking as a base idea it would allow you to put a lot of things from thrives earlier stages into it for example you could put the stats and abilities of users own land buildings on the planets which they designed in civilization and the environment of the planet will be seen in land battles and production stats of the planet etc.
I mostly just screw around in space skirmishes, but the system there is wonderful. The idea is that every unit counters another unit, and itself is countered. For instance, you win by taking out the enemy space station, which has a shield. Shields block laser weapons (and regenerate quickly), so you need stuff like Y-Wings, which have physical projectiles, to bypass the shield and deal damage to its hardpoints (roughly analogous to Tech Objects/Function Parts; they can be anything from laser cannons to the base's shield generator).
However, bombers are slow, fragile, and vulnerable to defending fighters (which use fast lasers), so the offender needs fighters of their own to counter. That's not even going into gunboats, capital ships (both of which have shields of their own, alongside all ships larger than fighters), all that.
In the actual game, taking a planet consists of eliminating the enemy's space forces stationed in orbit with your invading fleet. Once that is done, you then send land units down from orbit to siege their base and eliminate ground resistance, by which time the planet is yours. Since the invader does not get a base of their own, they have to be smart.