I think this game should have a campaign. It has such a great back-story and if they have a lot of missions, maybe incorporating each race. It could not only keep fans interested in the game longer, it could introduce noobs to the finer aspects of the game. I actually had to ask my friends about fleet logistics, capital ship crews, and colonizing planets, which wasn't explained in the tutorial.
Plus they could teach you things like capturing asteroids, star travel, wormhole travel, each race's super-weapon and super-ability, culture, and introduce each race's ships abilities. It would have been a great way to introduce Sins as a whole instead of the whole "learn by yourself" method. Also, it could make new players play all the races and see their advantages and weaknesses so they can pick what race they want to play.
I would have really wanted an Age of Mythology style campaign. Really long, and having you play each race. An obvious story-line would have you start out as TEC fighting the Vasari, then after immersing you in all things TEC, and after lot of good cut scenes, you ally with them and play them, and learn everything about them. Do the same with the Advent, probably fighting a common enemy, like the things chasing the Vasari. (through teamwork, all the races beat them and start an alliance) But this is just off the top of my head and they can probably find better writers than me.
I would just like three seperate campaigns for each race where you fight off the other two, or one where you fight as all races and end up fighting a common enemy, like Kronos in Age of Mythology. As long as they have the cut scenes to tie over the story, like at the beginning of the game, make sure to make each race is shown with their strengths and their weaknesses, Stardock could have had a great campaign. (Once again, I am not a writer and they could have come up with a lot better stuff than me)
They could have made Sins a really great game instead of a great game if they had an exemplary campaign.