User blog comment:Bronzey/Tying up the threads: possible storylines of Mass Effect 3/@comment-46396-20100321021650

Well Heroic, the only problem with that is if only 2 people besides Shep survived, that seriously handicaps your squad potential going into the third. That's probably the biggest reason for needing to stock ME3's squad with mostly new characters. Who knows how they'll solve this matter, but that's probably the main thing to consider.