Bored at work- here's my rewrite pitch for the Reapers and the final choice of Mass Effect 3

So, let's start with who created the Reapers and why they exist. In my version of the story, we learn that the Reapers were created by an ancient people whose mastery of science and technology bordered on magical. Their civilization fell into an apocalyptic civil war with weapons so powerful, they threatened the fabric of spacetime itself, leaving the galaxy in tatters and teetering on the brink of collapse.

The few survivors of their race, knowing their time was short and restoring the galaxy would take countless lifetimes, created a race of sentient custodians to oversee the work of repairing the damage which had been done, and gave them a mandate to promote peace preserve life. Then, they uploaded their memories and heritage into the first "Reapers" so that, though they might die, their people would not be forgotten.

It took thousands of years, but eventually, the Reapers restored the galaxy to a habitable state, and over time, life began to flourish again. The Reapers preserved and guided them, but in time, these new organics later developed similar weapons, and they, too, fell into war. The Reapers did as they had done before- preserve the memory and heritage of these people in the form of new Reapers and repair the damage.

This time, though, the work was arduous, lasting millennia. They came to realize that the damage to space time was even more severe, almost irreparable, and that another conflict of this magnitude would render the galaxy uninhabitable, perhaps even destabilize the entire universe. To allow this to happen again would be to fail in their mandate. A radical solution was proposed by the Reaper now known as Harbinger, to prevent organics from advancing to the point their creators had- a cycle of culling. The Reapers would allow civilizations to flourish to a point, and then return to harvest them and preserve them in the form of a new Reaper. It was brutal, but there was no room to fail twice- organics had proven themselves too dangerous for any other solution.

In this version of events, the Catalyst is accompanied by three alien VIs. The Catalyst concludes that, in building the Crucible, the current cycle had surpassed the Reapers and taken the first step on the path that led their creators to ruin. If the cycle were to end, a new solution would be necessary. The Catalyst introduces these three alien VIs as three different species which had almost completed the Crucible in the past, and each has their own proposed solution.

The first advocates for the destruction of the Reapers. They argue that organics will never, and can never, be free to find a solution to the question of war while the threat of extermination hangs over them. The Catalyst warns that destroying the Reapers means that this cycle would shoulder the burden of creating everlasting peace, since another cataclysmic war would render the galaxy permanently uninhabitable.

The second advocates that Shepard reprogram the Reapers and use them to enforce peace in the galaxy. With the Reapers under their control, they could end war through superior force and allow life to flourish under careful guidance. The Catalyst, however, is skeptical that organics would ever allow themselves to be ruled by fear, and that the fight against him may never end.

Finally, the third advocates using the crucible to broadcast Reaper indoctrination on a galactic scale. They would use this to return organic civilizations to a primitive, pre-spaceflight state and instill a fear of scientific discovery. Thus, organics may remain free and control the destiny of their own worlds, but they would never make the kinds of progress the Reapers fear. The Catalyst admits that this solution may be feasible, but that, in the perspectives of every organic species thus harvested, such a fate would be worse than death.

Lastly, Shepard has the option to reject all three proposals and allow the cycle to continue until such a time as a permanent solution can be found.