I know this is probably just a starting version of the game, but I've got some ideas for things to add later (or whenever you have the time).
-Game Modes-
+What Exists+
Deathmatch: Turn your opponent's starbase into orbital debris. Simple.
-Possible Additions-
Fighters and Feeders: Two/more Fighters start out, and an equal number of (for the time being) neutral Feeder races as well. The Feeder has a very small navy but is extremely strong in an economic sense (start them with multiple RGTs and a larger fund, build these units/factories faster but their own combat ships cost, lets say, 2x and build slower). Once the Feeder(s) is discovered by another race, they can begin diplomatic relations, selling resources to the Fighters in exchange for protection. (I'll just assume that underhandedness will take a backseat for the time being). If a Fighter can protect their Feeder, they will be given a resource boost every turn, making them much more powerful. If a Fighter loses their Feeder, well, you know the rest.

If a Feeder is under protection of one race when another first stumbles upon them and no combat ships are present, the Feeder must choose: look neutral, wheel 'n' deal with the person, making their Fighter
quite suspicious, or show their colors and be attacked?
Capture and Hold: A neutral base sits between two/four opponents. Inside are blueprints and the technology to build a superweapon that would give the navy that controls it total domination over their opponents. Capturing the base itself requires one of a race's fighting craft to enter the square with it. They then must hold onto the starbase for X turns. If the starbase is attacked, the fighters currently at the base are engaged instead of the base (obviously the base itself isn't going to be targeted). If the defenders lose, the attackers then move into the base and proceed to take it over, but all research information is lost, so the X turn count starts anew. Hold the base for X turns to develop the weapon (and win the game).
-Additions to gameplay-
Mining: Squares should have different yields in mineral wealth. Some rich, some poor. Makes the game more interesting. They'd probably have to be cast to a random byte when you first make the map, or something.
Low RU - 1
Normal RU - 2
High RU -3
Roll a dice or something.

Racial Stuff: Are races ever going to have specific abilities? A few ideas...
VUX: Limpet Cloud - Stalls any (ANY) one ship that moves through the affected square until that players turn comes up again. Each Intruder can use this ability 1 time.
Arilou: Blink - Teleports a Skiff to a random square within two squares from the point of origin. Risky, but could be useful. Each Skiff can use this ability 3 times.
Androsynth/Thraddash - Blazer/Afterburner - Lets the Guardian or the Torch move 2 spaces in one turn, but then denies them movement next turn. Each Guardian/Torch can use this ability 3 times.
Just stuff. If this sounds good, say so, I'll come up with more stuff.