Well i dont really know alot about the story of the universe but it seems like you are fighting your way to the core through an empire right?so if you had hexes like in ti3 and turned them over as you entered them revealing and conqured them as you went along...as i said i dont really know anything about the story of the universe but are the different orders against each other?.....i didnt say there was anything wrong with the game as it is...
I can see why the theme might sound more like a board game, but the game would really be way too random if you flipped planets as you moved towards the middle. I might build a deck focused around fleet strength and then move into a hex that requires a lot of ground strength. I can't take it and now I'm behind the players who flipped a planet they could take.
You could place all the planets face up on the map at the start of the game, but then the game can be better planned out leading to greater AP, which is already very high with my play group.
You would also need to add movement rules, which there is no foundation to build upon right now. I'm having trouble imagining a way that moving around the board is better than the card drafting system already in the game. Moving just adds randomness to a game that already has the right amount.