Although there are a couple of space maps in play already, there isn't anything that directly replicates a space battle.
I think that with 8 ships the idea gets a bit cluttered and lost - the two ships idea that you started with seemed to have a bit more potential, although you could do with adding more territories to it. Think of it something like the Arms Race map, where you have to try and take control of a single fleet, before warping across space to battle with the enemy - that sort of thing inspires me a bit more, and has an easier backstory to grasp with and make the game more interesting.
edit: It's always worth checking out other suggestions first, as there is a very similar idea by Spaceburger that was posted aa couple of days prior to yours - it might be worth speaking with each other and seeing if you want to team up??