After the HUGE deal they made of the "suicide" mission in ME2, that would be an epic fail on their part. A lot more jarring than it was with DA2 (though, in my case, apart from the Architect, everybody who was supposed to be dead was dead and vice versa).
I know it's a standard for BioWare games, but it's going to be epic fail if Shepard will have all the time to travel the galaxy looking for allies, shooting up mercs on uncharted planets and screwing blue/green/purple aliens while the Reapers are -slowly- reaping Earth... and still be in the nick of time to push the WIN!-button in the end.