Re: What's in YOUR future history?
My "Comsentient Alliance" universal history has most (if not all) of the points you and others have already mentioned: The war that helps to finally unify (mostly) Earth. The push outward by a unified humanity. The conflict between "the homeworld" and "the colonies". The meeting(s) with various other species. The dispute between those who want to befriend other species and those bent on genocide. Etc....
Of course, since the initial version of my future history was originally begun in the early to mid 1980's the projected calender dates are up for potential revision (eg: the radicalization of the Soviet Union by Muslim extremists and the subsequent merger of the USSR with a radical middle Eastern state and the ensuing chaos it brings the world was slated to happen by 1990-ish...etc).
Additionally I'd consider adding some cultural flavor. To pull an example from an old episode of Star Trek: one of the characters quotes from a poem that is famous throughout the galaxy and that would potentially be a "common knowledge fact" that children might learn in school.....etc
And, depending on if you have designs for more than on campaign genre (eg: Dark Champions circa 2010 and Star Hero circa ????, etc) how unified you might like those worlds to be. I, for one, am playing with having elements that show up in one era effect the other....maybe.
Just my slightly more than $.02US.
Oh...and yes, the Puma Twins and Artemis-Alpeia as well. Or at least analogs to them.....