I just wanted to contribute a few quick thoughts to the forum/community about Sins.  I enjoy the game, played two long sessions of it already and plan to play more.  I like the depth and complexity.

However, I must say that I think the ball was dropped a bit on tactical combat depth.  Simply stated, Empire at War has more tactical combat depth than Sins.  What I keep hoping for is something that will rival, at the very least, the tactical depth of Master of Orion 2.  More preferably, I would like something that rises to the level of Starfleet Command in tactical depth.  The one and only thing that gets me down about Galactic Civilizations 2 is its conception of a starship as a sum of hitpoints that, when depleted, exhaust the ship.  I thought that Sins would evolve beyond that conception; unfortunately, it did not.

For a sequel or an expansion, I really think that starships should be portrayed not just as hitpoints, but with hardpoints, internal/external structures, and systems.  Destroying a ship's life support and bridge would be difficult since those would be the most heavilly-protected areas of the ship.  But accomplishing that should effectively destroy a ship that has otherwise received little damage.  Alternatively, destroying all a ship's weapons may leave it still sitting there, but effectively useless in any capacity short of self-destruct.

Expanding on this, it should be possible to capture crippled ships, rather than destroying them, disable them, etc.

Empire at War only achieved the limited goal of dividing a ship's hitpoints across various systems--individual weapons, bays, shields, engines--all of which still needed to be exhausted to destroy the ship.  That's still not the concept that I think should be employed, but it was a bit disappointing to see Sins fall short of even that.

Anyways, that's just my 2 cents.  Everything else about the game feels great, or minorly tweakable (like diplomacy and the value of defensive structures.)