I'd have aged Shepard up. At the end of Two we know the Reapers are coming but we also know it was supposed to take a long time. ME3 cheated and said they got through somehow but that's not what ME1 left us with. Their backdoor into our Galaxy was shut. I'd have given the game thirty years to play with. You're an older, wiser Shep. You've helped bring the Galaxy into a fighting chance. Chased down leads, found technology, circumvented their cycle and when they finally came, you'd be ready for them.

Instead of "WAR IS HORRIFYING" through the violence on the front lines, the game could have explored all the people you came into contact with, forming one last team to take on Harbinger with all the weaponry you could muster. A grizziled team of A listers, all ready to fall over and give it to the new generation but one more fight to do before then. You can't have three games telling you there may be a chance, then be told you never really did and nothing you did mattered right at the last 10 minutes and get away without some flak.