Learning from Andromeda, Lessons for the Future.

Quality of plot is not subjective.
Liking a plot or hating a plot has nothing to do with quality.

That's not what I was getting at, rather: Andromeda is, in no small part, about the struggle for survival on desolate worlds. I'd actually hazard to say that this is the central conflict of the game. It is the drive for survival that pushes the entire plot forward. Given that this is the central conflict of the game, it is unsatisfying that its solution is merely flipping a switch, not ingenuity and compromise.

As for ancient mysteries: ignoring how poorly I think this motif was implemented, I know it can't be the central conflict, nor even much of a conflict at all. You never really grapple with the mysteries. You fight against someone else to control it, but never to you really struggle to comprehend or truly explore it like in, say, Rendezvous with Rama or The Anvil of Jove. In fact, by having the central conflict be against a simple antagonist, it greatly detracts from the survival narrative.
I'm not annoyed that this is what they do, I'm annoyed that they exist in the first place. Again, you're thinking very much within the context of the story we got, not the story we could have gotten. I understand what they do and I understand their function in the story and I even understand that their function is necessary in that story, but the story we got didn't need to written that way. 
Not at all. The difference between the vaults and the relays is that the relays are the basis for the core conflict of the trilogy, the vaults are the solution. The original trilogy explores the conflict that arises when intergalactic species; the mass relays are necessary for that conflict to arise, because we currently know of no solutions for FTL. They also, until the end of the series, which ruined everything, aided the conflict that arose from blindly trusting "eldritch" technology.

If the conflict of Andromeda is indeed the struggle for survival on barren planets (which it should be), then the vaults only serve to undermine that conflict by providing a simple solution. Because survival is reduced to essentially just flipping a switch, we lose out on all the character growth and agency we'd have by creating our own solutions or compromises.

If the trilogy had been about the struggle to attain FTL travel, then yes, you would be correct, the vaults and the relays would be the same thing, because a mass relay would completely undermine the struggle our characters would have to go through
You wouldn't have to play Watney, but that doesn't preclude others from being intelligent. Offloading plot advancements to ancient technology or an AI just computing the answer take away agency from colonists who could be solving things on their own.
No, its near-universal criticism proves my point further. People enjoyed the show more when the characters had their own agency and were solving problems on their own. When all the God stuff started creeping in, the show became very contrived, much like Mass Effect

What the different requirements of each individual are does not make a plot good or bad or have quality.
Same with how successful the game is.

Yes it is. I think Picasso paintings are terrible and he was a terrible artist. Subjective opinion.

Yes, but do you disagree that it would take vision?
And as always, I differ in that I value the artistic agency over player agency.

The point of a game were failure is the only outcome is to deliberately disrespect the player's agency, presumably to make some statement about the unfairness of life or the impossibility of compromise in extreme circumstances or whatever else. BioWare could also, in a stroke of ironic genius, make a game that accounted for choice so much more intricately than their previous games, but that it always ended in some distinct failure state. So long as the point is coherent, salient, and emotionally resonant, I'll let the author treat me as badly as they want. 

And yet you dislike Andromeda's plot, therefore it's bad quality?

No, I as I said liking a game or not has nothing to do with quality.

I am not judging the plot from the point of I like it but by the story the writers created.

That's a fair methodology.

I rate the fictional elements of video games differently than those of books, film, etc. - because they serve vastly different purposes.

Honestly, Mass Effect has always been riddled with plot holes, inconsistencies, wacky space magic, ridiculous technology, mcguffins, deus ex machinas, out of character moments, nonsensical character shifts, hurr durr dialogue, etc.  I don't know why MEA should be held to different standards than MET.  I'm just along for the ride.

I don't look to games for literary masterworks, but for a space that allows me to co-create a narrative for the character I'm playing.  The more RP space a game provides, the happier I'm going to be in that world.  MEA gave me plenty of space and allows me to create a variety of different character narratives, punctuated with some major cinematic drama, so it's high quality for my needs.

Ok you just lost all credibility.

Explain, then, how you've come to the conclusion that the plot is objectively poor quality.

Because right now, you're not making any sense.

And should be thusly criticized. The main plots of those games simply weren't that good. Thankfully, they were not nearly so boring and stretched thin. Side arks, chiefly the Genophage, maintain a high standard of quality in spite of the narrative they were intended to support and make the trilogy quite decent as far as Science Fiction media goes.