Off topic: If EA makes this game Origin exclusive, then I really don't fancy its chances.
On topic: It doesn't fucking matter. It's incredibly obvious that the results of the final battle will be bad if someone intentionally fucks everything up. Like Mass Effect 2, it's going to be mind numbingly easy to avoid this, because Bioware - as much as I love them - seems to, most recenty, at least, fucking suck at this sort of thing.
Remember, for a moment, Heavy Rain. In order to save your son, you had to go through five challenges; things like cutting off your own finger, or murdering a stranger you knew nothing about, for no other reason than to save your son. You had to do at least three of these challenges to even have a hope of saving your son, and all five to make it a sure thing. Even then, you still weren't guarunteed a happy ending, depending on what the other characters had achieved, as well.
Each of the challenges you had to complete was challenging in it's own right, and it came down to some seriously hard decisions about what you were willing to do to get a happy ending. This is the sort of thing that Bioware should be striving for.
Instead, what we're going to see are more diametrically opposed choices that really won't matter because the results will be the same. Not a single decision that we made in the last two games will have any *real* effect - ie more than a cameo - on the outcome.
Getting off topic again, but they even fucked up their attempt to make their black and white morality system not so black and white. The Paragon was supposed to be an idealist; someone who would not sacrifice their principles, while the Renegade was supposed to be someone to whom the ends justified the means. Instead, we get a naive, head in the clouds, light side of the force, way of the open palm nice guy, and a jerk who punches reporters in the head. Really off topic now, but that SHOULD NOT HAVE FUCKING GIVEN RENEGADE POINTS.
The EC crew made an interesting observation a while ago. During - spoiler alert - Legion's loyalty mission, you are given the choice of brainwashing or destroying the Geth. Instead of considering the ramifications of brainwashing an entire species to die for you, as opposed to removing the threat entirely - Bioware opted for the simplistic approach. Good guy saves them, bad guy kills them. The EC guys pointed out that both decisions might have resulted in Renegade points, but Bioware didn't consider that. Even more irritating, they didn't consider that by their own definitions, the point results should have been swapped. The ruthless Renegade would have brainwashed his enemies to fight for him, while the Paragon would have either killed them (a difficult decision that should possibly have given Renegade points anyway) or - being idealistic - left and decided to wait to face them in open combat.
But the real problem is that none of what I just ranted about will FUCKING MATTER, because Bioware seems to have mastered the art of giving us the illusion of choice. This won't - mark my words - boil down to anything more than a cameo, because choices aren't what matter in Mass Effect - it's the illusion of choice that counts.
And that, my good fellows, ties back into the very first point that I made. There's no *real* risk of losing, because, mark my words, it's going to be the threat that's important - the illusion of real danger is but one aspect of that. Besides, Bioware hates making players face consequences for their actions - we all know that.
Argh, damn you TOR, for stealing all of Bioware's *actual* talent.
/edit
Wow, that came out rantier than I meant it to be.
TL;DR: We can lose? Well, congratulations, Bioware, for adding to the facade of choice in this game. You know full fucking well that there's no *actual* risk of someone unintentionally losing, and so do we, so why even pretend? In fact, why the FUCK DO YOU - crap, I'm doing it again. I love Bioware, and I adored ME1, and liked ME2, so I get the treensiest bit annoyed whenever I think of how much better this series could be, or of the bleedingly obvious things that it's doing wrong. For as much as I loved it, ME2 was railroaded. Even ME1 was, to an extent.
Oh, and a note on the point based morality systems; the most powerful choice in the entire series was between Ashley and Kaidan, and that didn't use the morality system at all.
) squadmates in to a glorious final battle, just think about it bullets and biotic flying, please...