if you thought sins was the only example of that type of gameplay, you are quite wrong, Hegemonia was I think a closer match, it came out in 2002, an awsome game, in many ways a precursor to sins (almost like sins was a sequel to this game) some of the things the game got right:
the 3rd D, it had true 3d movement like HW
the sense of a breathing comerce underneath what you where doing (civie ships, salvage teams, kinda got the feeling like there were actualy people trying to live in your war)
managing you empire was acualy HARDER than the war part, whole planets could just up and die from one disaster or another if you wern't diligant
absolute bleeding edge GFX for it's time (ship designs look as if they were riped right out of the movies, again for it's time)
but most importantly........ABSOLUTLY THE MOST BEUTIFULL DEATH FX, EVER, with out question, perfectly cought the cinimatic quality of ship explosions before everyone went the route of blinding lights to cover bad fx up
seriously, the under apreciation of this game is an outright crime
but in the terms of conquest, it was certantly inovative for it's time, but it never really felt like an empire to me, more like an exuse to string maps together, but I would certantly play a mod for it