I am playing and really enjoying this game, but I think the creators missed a golden opportunity to create campaign here. The game itself is so well suited for campaign it is not even funny, it is better suited to have campaign than any RTS I know. Here are the reasons:
1) The game is extremely complex. It is the most complex RTS I know up to date. Each race has so many research items; each ship has so many abilities that I am still lost. Having campaign could gradually introduce player into each race abilities, thus making the leaning process much more fun.
2) Each game takes a long time, longer than any RTS that I know. That means that the campaign could have been played on the same map for quite long time, with new missions and things. So that you would not have to play the multiple new maps with some intermission in between, each time doing the same base build up over and over...
3) At the same time, the pace of the game is not chaotic as with most RTS game, it is more like TBS, so the player could chill out and get more involved into story line than with the clickfest.
4) It would be a perfect way to show off the beauty of the game. I mean in skirmishes you do not often put cinematic mode and zoom into the battle - you have to do the battle itself. But the game engine is so powerful! With everything at max, I can see so huge battles and each ship is shown in so much details! Granted I have powerful card (8800FTX) I still think game could show off lots of beauty even with moderate system.

So, sign here if you want expansion pack with campaign, or just post your opinion.