My wife, a very casual WoW player, really likes that the expansion has a strong emphasis towards leveling and having a cool new alt to work towards. She has had just enough time since Burning Crusade to level one character to 70, do some lightweight dungeon stuff, and play around with an alt or two.
She, like I, burnt out on the hardcore endgame some time ago (during Naxx) and isn't too eager to return to raid scheduling and high-end guild bullshittery.