yes, but those people it initially 'ticks off', is due to the fact that it's taking place 'before' other events we've experienced.
Whereas the alternative is ticking off (or atleast contradicting) every person who did not pick the one ending selected by BW as the 'canon' choice.
You see the difference, yes? One is based on preconceptions, the other is literally railroading on the part of the developer. I know you have a distaste for "prequels", Kaiser. I don't really define a prequel as others do. But everybody has their perspective. See, I think there's some interesting stories left to tell in the Star Wars Expanded Universe before the Empire is even defeated in RotJ. Hell, I think as long as there's millions of people in a galaxy, then there's millions of stories to be told. Regardless of the state the galaxy is in.
I don't write off the fantastic journey that is Saving Private Ryan because I know that exactly 4 years after the events of the film that Hitler commits suicide and we vaporize a quarter million people over in Asia. No, to me....those are still their own stories.
Idk....if the next Mass Effect becomes an unforgettable individual/companion/group journey taking place 'before' the events of ME3 (or sh*t, why not ME1?).....I'm not gonna look at it and be like "Oh, but what about the Reapers?", and judge everything by that speculation alone. Whatever type of story it attempts to tell, I'll judge it on its own merits.
Let's face it. Fans are going to be upset regardless. Mass Effect is a minefield of an IP. Also, you can't discount the people who simply don't like how the trilogy ended. Setting it in the future allows the franchise to move on from that, but setting it in the past and it's tied inextricably to it, regardless of what the story is about.
The reason I don't really give much consideration into comparisons between this hypothetical game and stories like Saving Private Ryan or The Last Samurai is because it gives no consideration to the distinction between being a passive observer or an active participant. Do I find them to be interesting stories? Sure. I think Saving Private Ryan is a great movie (The Last Samurai is meh imo). But, do I want to actually play the ME equivalent of Captain Miller or Nathan Algren in a choice-based video game? F*ck no. Reading or watching a story in a book, movie or TV show is just not the same thing as playing a choose-your-own-adventure game. As for Star Wars, I really can't take any of it seriously, because the prequels, in my opinion, destroyed the entire franchise in pretty surprising ways.
I just want to point out the irrelevance of Hitler and Japan in Saving Private Ryan. Neither mattered, because neither contributed to its narrative. Hitler could have already been dead and Japan could have been nuked at that point and I would not have cared. The movie is not about the entire war; it's simply about rescuing one man who lost all of his brothers. On that end, the story was told and resolved and we saw him grow old in the present.
Another small concern I have is one of plotting. A small scale plot on the level that I think you're getting at here needs to be intricate and engrossing enough to keep the player invested for more than 20 hours of gameplay, lest it becomes another game of glorified side missions, as you've said Mass Effect 2 ended up being. Do I believe that the Mass Effect team is up to such a challenge? My answer is no. BioWare has a penchant for making big scale stories with a very simple premise, and everything else is a side plot that may be resolved in a couple of short missions that amount to maybe an hour or so of gameplay. I simply have no faith that they can create a Mass Effect game that can sustain itself on a small personal story in a space epic backdrop. I don't want another galaxy-consuming super threat that insidiously rants about how all will bow before it and every world will darken in its shadow, but I don't believe that they can pull off its polar opposite in this setting either.
Perhaps you wouldn't say to yourself "But what about the Reapers?", but plenty of other people would. I would be doing the same thing. Any game set in the past in ME is automatically tied to it. It doesn't matter what it's about; it will always be there.
Thinking about it, I think the biggest problem is the intended goal with this story: avoiding fan backlash rather than focusing on a point of interest in the timeline. The story you're suggesting is nothing but the former. It's also a trap, because a story that's vague enough in details to take place at any time means that it's just obscure dicking about in the galaxy, and anything of note would have to be fixed in its outcome. Do you know what avoids fan backlash the most? Ceasing all development of Mass Effect and moving on to something else.
Wouldn't you just as well be able to judge a story set in the future on its own merits, regardless of whether or not it contradicts the choices of certain players?