Damaged characters are more interesting, but there's always the question of how damaged they can be before people find it too hard to read about them (or find them too unsympathetic to care). On the visual thesaurus site, novelist Laurel Dewey writes about this issue:
He told me to tone her down but not lose
that edge. She was really, really full of rage in the first draft. When I gave
the draft another read from his point of view, I realized he was right. Jane
Perry was extremely irritable. She was a drunk. She was abrasive to superiors.
And here she was in the book being in charge of a nine and a half year old
trauma victim. I put her in a situation that was basically out of her control.
But her character grew and evolved via this child she reclaimed. And by the end
of the book, Jane reclaimed some of her own innocence, too. I had to go back
and I had to soften her. Now that was very important. My editor told me I had
to give her much more vulnerability and allow the reader to feel compassion for
her. Well, when I first heard that I thought, oh my God, if I do that I'm
cutting her off at the knees. It was a tenuous situation. I didn't want to make
her too soft. But, vulnerable, yes -- I certainly allowed her vulnerable
moments that make her more human."
This is one of those issues where it can be really helpful to get an outside opinion, because as writers it's hard to be objective about our characters.
(for a book that takes you all the way from your first idea to publication of your novel, see YOUR WRITING COACH, published by Nicholas Brealey, available in book stores and online. Endorsed by Robert Cochran, co-creator of "24" and agent Julian Friedann and ready to help you achieve your writing dreams today.)