CharlesPhipps wrote:Were Bioware to hire me, I would use the "Deus Ex" model of "all endings happening" to explain what happened.
That feels weak to me. One of the big criticisms of ME3 is that it made a joke of the notion that your choices mattered throughout the trilogy; doing what you suggest basically makes even Red/Green/Blue ending even
more meaningless. Not only did they deny you any real chance to have an impact at the end of ME3, now they'd be writing that off as well. It's saying, "Screw it - all of them are true, and Shepard's story doesn't get a proper resolution. Have fun with this new cyberpunk world we've put you in!"
The best way I can think to incorporate all three would be to treat them as parallel universes created by the Crucible, whose true purpose was to re-shape reality to defeat the reapers. Out of all the infinite possibilities, it was able to determine only three possible ends where the Reapers are defeated - Destroy, Control, and Synthesis. Shepard's role was to serve as an organic computer to evaluate which route was the best - shockingly, a hastily mashed-together superweapon built by disparate cultures tens of thousands of years apart who somehow don't even know WTF they were building is not 100% reliable.
Instead of creating a single new reality, it created three of them... and now they're starting to meld and overlap, randomly re-writing the universe over and over again. The PC, for technobabble reasons, is one of the few individuals who somehow manages to notice something is wrong. Your objective is to explore where the three universes diverge, and figure out a way to fix it.