I think Maggie became more conspicuous as the show progressed. Case in point: she lived at Collinwood. That alone enabled her to be on the show more often than she had been. She was in many if not most of the "Game" episodes involving David and Amy pre-1897, and during that time, I think she showed strength and determination in the face of a great evil. Also, in the Leviathan plot, she was pretty crafty when she [spoiler]fooled Jeb into thinking she was one of them.[/spoiler] True, she wasn't much of a presence in the Summer of 1970, but really...no one else was, either, except maybe Julia and the Ghosts, of course.