Sins is fun without a campaign, just like Master of Orion had none, but was still incredibly fun.
But we know the game "Homeworld", which was incredibly fun, too. If they plan to do expansions, a Homeworld-style expansion would not be bad.
There are so many possible interesting scenarios for a campaign:
TEC & Advent & Vasari UNITE!
... because THE UNKNOWN ENEMY (tm) arrives, destroying planet after planet. This unknown entity is a beast from the "negative" side of the universe, that is total barren of organic life, but full of life based on silicone, aka Pamela Anderson. SCNR... There is no compromising with such an enemy of life, so your job is to destroy evil at its roots and find out how to do so - and save the universe.
I hope they come up with a better, less trashy, story... 