Like i said only canonise the ending and leave everything else alone, i don't mind the destory ending being canon if we get a decent story out of it, I would go into more detail but i'm an touchpad and can't convince you.
If you canonize an ending you're telling everyone who picked a different ending in a choice based narrative "You chose wrong"
The forum will be aflame...again...
I mean there was an uproar over Udina being the human Councilor and that doesn't hold a candle to what you're proposing.
That is not an answer to my question.
What makes canonizing one ending better than simply going AU?
I think this is the main tearing point in terms of fan opinion. I think both of you (myself included) were in the dark days of BSN following the release of ME3, and that is not a sight which I wish to repeat. Going AU on the franchise, while drastic, would allow a blank slate for the devs to work. Draw on the experiences of the trilogy to make a game with thought out themes, concepts, and most importantly, stories.
The main problem is, like Drone223 said, that the fans will whine and complain no matter what happens. If they decide to canonize an ending, and then they realize that everything is trivialized-forgotten, the old-time hardcore fans will have another rage, saying that ''My choices didn't matter!'' again even though they shouldn't.
On the other hand, trying to go AU is a bit like pushing the reset button. You will obviously have to change some pieces of lore/history, since I doubt the devs would decide to do AU just to erase the endings. The tough part is abandoning all the themes and events from the trilogy, and then trying to recreate them from a blank slate. You might get a continuation of what you had in the trilogy, but you might also deviate a bit from the original vision from the original trilogy. We all want something new and fresh, but how do you walk that line and keep it balanced? You get something that is ''fresh, but recognizable''. A lot of people want more of the same Mass Effect, and it's easier to do that in a continuing line (sequel) than it is in an AU.
Basically, I hope the devs remember what made Mass Effect so special and try to follow the route with whatever option suits them best. If an Ark type scenario where all species are sent to an unexplored part of the galaxy away from the Mass Relays sounds like a good story, go for it! Same thing for an AU or canonization route. Just make a game that will make the most people happy and will assure a good future for this franchise.