He has admitted, though, that his characterisation of Zatanna largely stems from his being married to a woman who looks just like her and does very similar things...his wife.
"Major Flaws" also fits into the Mary-Sue category, or rather its sub-category "Sympathy Sue". But the fact is, without other characters - mainly Joker and Poison Ivy - she doesn't have enough depth to support a book. There's no real character there.