The more I think about it, more I see no way for Bioware to save Mass Effect from it's shittastic ending.
I personally would retcon it, but ignoring the mess and basically re-building the universe from scratch on another corner of the galaxy may work. Keyword, «may».
Even if they find a way to relocate some of the alien races to Andromeda (secret Krogan / Asari /  Turian planet anyone?) and even throw some rogue Reaper there, a good deal of Mass Effect was about Shepard and even thou I can accept not playing him anymore, it would be cool to see mention of him and of other fan favorites like Garrus and Wrex.
Like I said before, this game could be called «Space Warp: Andromeda» and nobody would know better, but from a economic point of view, it pays to use the Mass Effect tag, and of course, even if they only recycle some basic elements of Mass Effect is still easier than building an universe from scratch.
The game may be good, even awesome, but because it's a AAA sci-fi game with good writing and not because it's Mass Effect.
And of course, the question remains… will Mass Effect universe be!!!forever contained on the far corners of universe? Are we never going to!!!see Earth and the other previous civilizations again?