I can't believe I'm 2 days late to this news… What a huge, albeit not surprising thing to hear that Mass Effect is going to return at some point! All you naysayers can suck it, I loved the series.
I'm just horribly afraid they're going back to the prequel idea. No one cares how the First Contact War played out. It happened, and we know what happened. No one cares about the Protheans. No one cares about the early days of Cerberus, etc.
I'd be totally cool if they dug up Shepard, even, though there are ample other stories they can tell in the post-Reaper worlds.