the combat 'board' would have to be a lot bigger. I think there should be battles with as many sides as there are faction in the game.
Have you ever played a multiplayer RTS with like 8 teams at once? It becomes a massive game-theory problem, I suppose, since you don't know what choices your enemies will make in relation to their other enemies, which are also your enemies. The most compelling and risk free strategy is to hold back and wait for them to destroy each other. So with all parties doing this, things will usually become a big mexican standoff. It's just so risky and unpredictable, essentially a lottery, to commit forces in this kind of situation, so everyone tries to back out of it and then maybe secretly chase down their highest priority enemy while nobody else is looking.
Unless the objective being fought over is VERY compelling, like status-quo breaking technology, or a rich planet or something that's worth risking an entire fleet for. Then maybe you will start trying to harrass enemy A and take opportunistic swipes, and thereby distract them enough to tempt enemy B (also your enemy) into making a large scale attack against A, and hopefully also weaken themselves as well. But will B attack you instead of attacking A? And what's going on with C, D, E, and F over there?
Anyway it's really interesting. However if it were implemented I think both the (smart) players and AIs would almost always try to avoid this kind of situation unless they had overwhelming force against all other enemies combined. But sometimes you might HAVE to fight in the pitched multi-battle, and hope for the best that other enemies would fight each other instead of you-- and boy then things would get fun.
So it's something that would be fun and cool to have in SS, even though you wouldn't see it happen much, except when like a gant Tri Tach patrol wipes out a pirate scout and hegemony scout who were fighting each other.