I had a great first impression when I first played Sins. I see so much potential for the developers to make a great game. I'm basing my suggestions on the games character, and think that it would help Factions to be able to exercise more military power and experience tide-changing events as well.
An idea I'd like to add in that I think would rock in this game is to make the Sun capturable. Allow for a faction's larger military presence in the sun's area to capture the sun after a bit of time and then allow them to bring in(possibly mobile constructors) and build Tactical Buildings. The Sun when captured gives a gained militarily bonus around the sun to the team that captured it. So it can become a base of operations
After imagining playing this scenario I have no doubt that this would really give some depth and fun-value to this game. I picture teams will attempt to aim for taking the sun near the beginning, and some players would choose not to bother as they build up a larger army and planets before claiming an interest in the fight at the sun.
Another idea is to make the capital ships more like Rooks in a chess game, they should be a risky investment. IE, much more expensive than they are now. Taking much longer to build, an increased scale in size and made much stronger in firepower and armour. When a capital ship joins a fight it should be a larger presence on the battle field than it already is, perhaps targeting multiple ships at once.
At the moment there is a point where it pays to spam the most capital ships, I think this takes away the importance of the idea in placing them strategically. Perhaps lower the capacity to a dozen ships; placing more emphasis on buffed up carriers for late-game firepower.
Leastly I suggest that the time for capital ships to jump should be lowered so you can move them to important locations quicker.
Thanks for reading and considering.