Didn't Bioware say that ME3 would be the conclusion of Shepards' story though?
They did. But they now say this isn't the last we'll hear of Commander Shepard (their words). The pop up after the ending saying to continue Shepard's legend with DLC also basically admits they ain't done.
Imo, take everything they've said in the past about ME3 and just ignore it. Get less BS from politicians than Bioware devs/marketing people these days.
Meh, they'll probably discover a clone of Shepard somewhere in cryo stasis after project lazarus or something daft
Sad thing is, with the way their writers seem to be going this wouldn't surprise me in the slightest.