I was reading about them here when I stumbled upon the Waif. Not my favorite at all. In fact, this type is almost like an anti-heroine. But she used to be, in romances, a favorite. So I was thinking that she's outdated.
Back in the day women had to rely on men for a lot. Finances, a home, comfort. Think of the countries where a woman couldn't own anything! So I think the waif was popular because women could relate to her.
But now. . . in America a woman can do and have and say everything a man can. In theory, at least. I'm willing to bet very few women can relate to the waif. We're independent and that's the kind of heroine we want. A woman who's strong and makes decisions.
Adios waif! Let's come up with a new heroine.
Just my thoughts.