@EgoMania
"....What I do wonder about though is this: As soon as you get a guaranteed option that ensures that the base is blown up AND you get to save all the Angara, why would anyone even consider the other two choices anymore? That's what I mean with invalidating other choices..."
And that is a great question to have. I feel like I answered it in my first post though and someone else answered this with a ore detailed idea I believe it was @CasperTheLich.
But let's be real, with everything that's been said, it is easy to miss and or forget something, lol.
Anyway, my solution to this would be to make it to where it would impact a later situation negatively. The other person had an idea where I believe they said maybe we would have been able to negotiate our way out of something, but the Kett know you didn't keep your word so that's no longer on the table.
As far as already existing things, I believe there is a part where a Kett offers to help you out in some way to take down the Archon, but if you didn't keep your word, perhaps they do not provide that help.
So in short, you just make another key decision be affected by not keeping your word. Another reason might be because they could have it negatively impact your relationship with others, I guess since this game doesn't handle relationships like Inquisition, it would matter much. In that game you could lose someone.
But yeah, SAM is crazy powerful and I think our race is too, but that's all that typical we're the player type stuff in my opinion. And because of that, even if SAM turned on us, SAM would suddenly be limited in a way that he wasn't before.
And despite him being so powerful, there are times where that ability seems to fluctuate when they want it to. Meaning, for an AI that can figure out how to disable a shield, there are times where he seems to struggle with doing something I'd think would be easier for him to do. Nothing specific comes to mind right now, but yeah.