How is it interesting though? You'd have machine gods basically playing Big Brother over the whole galaxy. Again, unless Shepard Reapers basically pulls some bullshit excuse to sit out on galactic conflicts, which directly contradicts ME3s endings of how they use the Reapers under their control, what conflict is there for the series to explore? If there is a war or major conflict of any kind Shepard Reapers will be there to put a stop to it and play galactic peacekeepers. It's an inherently static world at that point as Shepard Reapers can fix everything. They don't just have overwhelming monopoly on violence and force, but they are a source of near infinite possibilities when it comes to tech and scientific advancement for the galaxy. It's as utopian an ending as much as Synthesis, just with machine god overlords. Literal Deus Ex Machina able to solve every problem that could arise.Control is the only option that leaves the Mass Effect universe in an interesting place.
The only thing you achieve by choosing "destroy" is making the universe smaller, undoing huge parts of its worldbuilding. It's a worthless option.
Synthesis has always been a joke ending. Nothing quite like achieving world peace by forcibly altering everyone's (and every hat's) technobiomagical makeup.
This is a short-sighted concern anyway. Even if the choice backfires, at least it backfires in an interesting way.
The few brief shots of the post-control world are absolutely fascinating. I want to see what life looks like when everything you do happens in the shadow of a giant robot cuttlefish cop.
The only real interest story to come form that would be one where people rebel against said Big Brother and seek to give sentient life the chance to do as they wish and without the interference of machine gods doing what is best for them. Which is pretty much just a retread of the ME Trilogy all over again. Sentient life fighting to take control of their own destiny from the Reapers. That's creating a very boring and narrow president for the series if that's the only kind of story it can tell. That or dramatically escalating the scale of conflict by introducing a threat that even the Reaper led galaxy is helpless against, which is just absurd power escalation.
Destroy at least sets the galaxy up for major changes and upheaval that can result in both advancement, regression and conflict on their own merits and failures. Not at the whim of some all powerful overlord. There's just way too much baggage and far too many contrivances required to make Control or Synthesis work as a basis for the series going forward.
