Provided the forge tools allow us some robust triggers I could see a real cool campaign being made with just 3 maps. One for each species, all based on the lore.
1st - Vasari First Contact Scenario - Giant map full of TEC that you, the single Vasari player, must defeat. Just needs a few talking heads explaining how it was the first time the vasari met the humans on some outer systems, how underprepared the humans were, how they will have an easy time subjugating these people before the unnamed threat catches up with them, etc. Little finale bit explaining how in the years since then the TEC have formed and humans have gotten their act together.
2nd - Advent Return Scenario - Giant map full of TEC and Vasari in conflict that you, the single Advent player, have to defeat. A few talking heads explaining how the Advent just came back for their birthright, how how nothing will stop them, few blurbs from the TEC cpu talking about how they assumed the Advent all died out and Vasari cpu simply threatening everyone with doom and gloom unless they surrender, etc.
3rd - TEC System in Chaos Scenario - Giant map full of all three sides, player controls TEC forces. No real plot here, just some talking heads to indicate the escalating conflicts as you lead the TEC to victory (in this battle, not necessarily the war). And as soon as you wipe out the other players when an ingame cutscene pops up, notifying the player that ou have lost contact with some of the outlying TEC systems. Then lost contact with a few more. Then a few more. Big dramatic end, hinting that whatever was chasing the Vasari is coming. Or whatever, entirely up to the ICO guys, however they want to keep us hanging.
None of this would really tell us anything we don't already know, but it would help illustrate the motives of the species and let us hear/see them ingame as more than just other players.
I am sure there will be something made similar to this by the player community, but it's never quite the same as an officially endorsed plotline and professionally made scenario (also official voiceovers are 100x better than fanmade ones