I'll play devil's advocate here and say Hester is NOT a worthy role model. She says that the letter has done its job, which is presumably to cause repentance for her indiscretion, but she would clearly have done the same thing again if given the opportunity. She has learned nothing in that regard. She lies by omission when she does not reveal the true identity of her former husband--or of Pearl's father. Though she does learn to control her temper and her bitterness, she says she is afraid to pray for fear she will pray curses down on her enemies (in this case, the hypocritical ladies who find her good enough to sew for them but look at her as a shameful, "fallen" woman). Hester also encourages Arthur in his deception (lies) and is even complicit in his maintaining a facade of piety in the town. While she does have the strengths outlined above, she is not necessarily worthy of emulation.
One of the reasons why I would say she is a role model is because we actually get a picture of her as a whole person. She committed adultery, bad to some people no big deal to others, but she also demonstrates great strength and a willingness to work hard and deal with social ostracism while still caring for people. Too many times I think we expect a "role model" to be perfect and we ignore the fact that knowing more about the entire person is helpful so that people don't aspire to be something impossible or think that they cannot make mistakes on the way to being something or someone great.
She's definitely a worthy role model. Here is a woman who really didn't do anything wrong (by our standards today, at least). To top that off, the person with whom she "sinned" is still running around with everyone thinking that he's great and wonderful. Hester gets branded with the A while Dimmesdale is still respected. If I were Hester, I'd be really angry about that. But she doesn't let that or the general condemnation she receives get to her. Instead, she is strong enough to fight through it.
So here's a person who's been wronged but who doesn't turn to anger or revenge. She's definitely a worthy role model and certainly better than anyone else in the book.
For the Puritans, Hester is set apart as a sinner; yet her nature demonstrates her strength and goodness. In Chapter XIII, for instance,
Hester's nature showed itself warm and rich; a well-spring of human tenderness, unfailing to every real demand, and inexhaustible by the largest....so strong was Hester Prynne, with a woman's strength.
Hester tends kindly the sick and the dead, and her letter comes to be perceived as meaning Able and even Angel. Further in the chapter, the rulers and the "wise and learned men of the community" are in accord that Hester's good qualities have had much influence upon the people. Not only does Hester perform charitable deeds, but she is independent of spirit: "She assumed a freedom of speculation."
In a time of the subjugation of women, Hester possesses an independence of thought, and is much ahead of her times. For, the "dark question" of women's rights in her society enters her thoughts. She perceives that there are three steps that must occur before women achieve independence: (1) Society as exists in her time must be torn down and rebuilt; (2) men's perception of women must change; and (3) women must undergo a "mightier change" by which the "ethereal essence" is altered.
Human for having sinned,but penitent, fiercely protective of her child Pearl, inexhaustible in her charity towards others, independent of thought and spirit, determined, and true to all, Hester Prynne, is indeed an excellent role model.
What actually makes Hester a role model is her ability to overcome great trial and turmoil in her life and create the best that she can with it.
Over the course of the Hester's perception in the eyes of the people changes. Her scarlet A changes its meaning going from the adulteress to the angel. Instead of being destroyed for the shame that weighed upon her for years after not confessing the identity of the father, society began to see her strength and valued her abilities to sew and embroider, not to mention care for the less fortunate.
Hester demonstrates great loyalty and resolve throughout the novel as well. I deem each of these qualities worth modeling. Because Hester does not reveal the identity of her lover for so long and because she endures the town's ridicule as well as Chillingworth's scrutiny, I find her a worthy character. I might not morally agree with her original sin, an encounter out of wedlock, but I do acknowledge that we all mess up. Hester doesn't let her mistakes tear her down. She accepts the consequences and makes the best of them. These qualities are worth admiration.