Gotta admit, I am cautiously optimistic about this. If Bioware did do some sort of "staggered ending" then in my books, it would go down as the single greatest peice of storytelling I've every had the pleaure to be part of. I don't mean an 'oh shit they're angry, throw something together' patch, by the way, I mean a proper, planned and well-written ending that took advantage of how people play games over reading books or watching movies. And we will be able to tell the difference.
If they just said "ok, we fucked up. We got too wrapped up in our own ideas, got too involved with out story and just forgot to take on board critisism. We're going to re-write the ending for all of you," and patched the game with something nice, that would still be good. Yeah it would be wierd, but it's not the first time it would have happened (think director's cuts of movies) To my knowledge, it would be a first for games though. On the other hand, for the price of a little wierdness, the story gets a good ending and we can declare all the current confused mess non-cannon.
Even if they only added a 30 second epilogue (and I am very hopeful of this, given their tweets) that explains how all life isn't doomed, stuck in the Sol system for the rest of its short existance along with a small ending for the love interest and crew other than "look they're on a planet!" it would at least give some closure. Despite what I've written abobe I don't hate the endings... I think they're badly written, especially compared ot the rest of the game, but I don't hate them and having some closure on top of them would fix a lot.