Sula is a smear of problems over every page of her namesake book, Toni Morrison's Sula.
In the storyline itself Sula is a problematic character. At her death no one cares but one, and leading up to her death no one, including that one (Nel), even likes her. In fact, Nel is the only member of her entire community who even cares enough to emotionally attend her funeral. Sula likes no one but herself, and herself she worships as an ultimate God. In her community, even in her dearest friend, she excites no love, only deep disregard. In the world in which Sula lives, then, she is far from being anything heroic.
Sula is equally as problematic in feminist reading analysis. For despite all of these negative personal and social qualities, she is utterly exemplar- to a major extreme- of a hero of the womenfolk everywhere. She is a character of intense personality- strong, hot-headed, and head-strong. She refuses to be anything but herself. Social norms she throws away, including- and especially- the social norm of womanhood. In this sense she represents a feminist hero, a true champion of full womanhood.
But it takes a full reading to accept this view. Before the tale's end, at which Nel finally realizes how socially transcendent and freeing Sula's strong female personality is, the reader can only see how foreign her extreme feminist personality is. Her womanhood proves to be more villianous than heroic. Rather than being socially freeing, it is in fact socially desctructive, a wrecking ball to community, family, and friends. But in light of Nel's final realization, Sula's impact forces a new perspective. For by it Nel is, for the first time in her life, effectively freed from the constraints of womanhood that have always been placed on her. She realizes she doesn't miss her husband, she doesn't need her husband, and she doesn't ever desire another man to love her like her husband had.
When Nel realizes this, Sula becomes her feminine hero.