But think back to ME1 and the mission where you'd eventually find Admiral Kohaku dead, where there was talk of Cerberus creating a super soldier. What better than to rebuild (clone?) Shepard when s/he died? Oh man.
Oh totally! Yeah, it'd be a little messed, but completely viable, if a touch unoriginal. However, knowing the writers over there, it will definitely have its own unique spin.
I can't think of any other reason, aside from the scenario painted above, really, for such a reveal (or lack thereof, as it were). Guess we'll find out in due time, but a human army of Shepards would be pretty devastating.