I still think that we need a 1000 FP-sized battle. At least one. At the end. But. All our ideas combined - the player has got to find a suitable planet (a very rare one!), set up a colony (like a castle in Mount&Blade), defend the entire system, and work against a clock - not an entire game-destructing clock, but just an in-system clock. When the timer reaches zero, some faction tries to capture your planet. If repelled, this faction gives up. If not, you lose the planet permanently. If you get the planet, you gain income and possibly some unique skills/ships/weapons.