Bioware's Mass Effect 3 extended cut DLC certainly answered lots of ambiguous questions. But one thing was still not revealed- during the destroy ending there's a 2 second pause which shows someone in N7 armor. Now the question stands is Shepard alive or not (I am sure many of us have already guessed it, right?).  BioWare UK Community Coordinator Tully Ackland has now confirmed that Commander Shepard is alive if you choose to go with the destroy ending. Ackland's statement on the Bioware Forums is as follows:  

"You may notice that in the "Shepard lives" ending, the love interest hesitates to place Shepard's name on the wall, and instead looks up as though deep in thought. This is meant to suggest that the love interest is not ready to believe Shepard is dead, and the final scene reveals they are correct."

There you go people,  Shepard is still alive and this gives us hope that a new Mass effect game with Commander Shepard may be possible in the future.