Personally, I don't understand people. Everyone says that BW cannot canonise an ending or make a sequel to ME3 without pissing off a huge portion of the fanbase. I don't really see that, but we could assume it's true.
So, let's assume it's true. Who are these "pissed off" people? Are they people who liked the ending(s) to ME3 and are frustrated or upset that their choice ending did not get chosen? Possible, but I'd have to think they are a smaller percentage of the population of "pissed off players". Are these people who are already upset with the endings and have sworn off BW products and the franchise altogether? Most likely, but then, why do they matter? They've already sworn off their "almighty dollar" so why should anyone want their input? And frankly, I'd rather have an artistic vision that's not beholden to the threat of cutting off funding.
I don't see BW making a canon ending (but it's wholly within their right as the IP holder) because BW loves player choice. And I think, no matter your feeling on the end to ME3, you have to acknowledge everything BW has said on the matter pertaining to player choice and artistic integrity. Those two things coupled together make me believe that the end to ME3 will not be touched.
And lastly, no matter what BW decides, if they make a good game; who here is not going to play it? Sure, BW could do something the vast majority of the community doesn't like or agree with, but if it turns out to be really really good and fun? Immersive? Everything you love about the series in a new experience... who here is going to pass on that? I definitely will not.