o me "meta galaxy conquering" sounds awesome, no doubt - however, it also sounds like Sins 2 rather than just something that can be done "overnight"
Actually, a meta-game like TA's boneyards could be done very easily and very quickly, and (strictly speaking) wouldn't even require any game-code manipulation.
Just have a galactic map, with different in-game maps representing each "node" on that map. (You can even re-use various maps in different places
), and have each race control a specific section of that space. Any given node will be controlled by one race, and if that control is in excess of X %, then they can "assault" any adjacent node with it. If an assault is launched on a given node, that basically means that player of race Y is there to play a game -- and a player of another race gets to meet him, and whoever wins tilts the balance of control in that node to their side. As a result, the more battles a race wins, the more they control that node. Once they reach a certain point, the enemy can't use that node to attack deeper into their territory, and after another point they can use that node to attack deeper into enemy territory.
