Sorry that I have not posted an update in a few days I've been steadily working on different parts of the game, and I will make some posts today about the work that I have done.
The first major change to the game was to add Trader Ships and Fighter Colony Ships, as well as AI for the Trader and Fighter factions so that they would know what to do with them. After that, I played some test games to see how the balance would play out.
Testing games this way takes forever, because each iteration you must start the game from scratch to see how it plays out with new values for ship costs and things like that. To deal with this, I added an AI for the Alien player, the faction that is currently designed for the human player. I had to create a somewhat complex algorithm for that AI in order to have it properly choose which flag to move when placing new flags on the map, but it seems to work pretty well.
Here is a screenshot of the 3 AIs battling it out:
The Trader Ships are the long lines of ships moving between almost every planet on the map. When they move from planet to planet, they perform trade actions which add money to the Trader player.
The shorter lines in the top right corner are the Fighter Colony ships. They must move colonists to a target planet, and then move back to their homeworld to refill the ship with colonists.
The red splotches in the bottom left corner of the map are the aliens. Their "fighter" ship is also able to capture star systems by eating them when in close range.
With all of this in place, I was able to set the speed of the game really high and let the AIs battle it out to see how the game plays and what kind of things are likely to happen during the course of a game. Based on the results, I can tweak the balance of the factions.