If you had asked the audience seeing Ibsen's A Doll's House the first time, members of that group would have firmly censured Nora for the woman she eventually becomes. In fact, while copies of the play sold out immediately, audiences were appalled that a woman would leave her family. Ibsen had to write an alternate ending that he called...
...a barbaric outrage to be used only in emergencies.
Rather than seeing the play as a human rights story (as Ibsen intended), debate focused instead on Nora's departure from marriage and children.
From a modern standpoint, Torvald is a Neanderthal. He does not see his wife as a person—not even an adult—but treats her like a child. While she did all she could to save his life, he can only worry about his reputation.
We can see the value of Nora's change in character in terms of her need to be treated as an adult, and an individual. While Torvald shows little regard for Nora's intellect, she demonstrates a keen resourcefulness. She forged her father's signature to borrow money to pay to take Torvald to Italy to save his health and life. She was frugal with her allowance and did some work on the side to pay Krogstad what she owed. In leaving, we can infer that life will not be easy, but Nora will survive. Kristine Linde is a perfect example: she has gotten a job at Torvald's bank. We can expect Nora would find a similar way in which to survive.
Nora needs to be praised for the person she is—not for the source of entertainment she provides for Torvald. Torvald treats her like a child, but he is not terribly responsible himself. He is either egotistical beyond measure in believing he will never be called upon to save Nora, or he is a hypocrite...or both. After the ball, Torvald tells Nora:
Do you know, Nora, I have often wished that you might be threatened by some great danger, so that I might risk my life's blood, and everything, for your sake.
In truth, when the situation presents itself later that night, Torvald's only thoughts are for himself.
Torvald's estimation of Nora's value when he believes he will suffer in society's eyes is evident here, proving that they could never be equals. He plans to imprison her in their home; she will not be allowed near the children; they will appear to be a normal family:
You will still remain in my house...But I shall not allow you to bring up the children; I dare not trust them to you.
Nora begins to see things of the world she never recognized before. Ironically, Krogstad (who Torvald so resents) is a better man than Nora's husband. Her sudden realizations will never allow Nora to return to the life she previously knew. She notes that her father treated her like a doll that he could manipulate; marrying Torvald brought more of the same treatment. Nora realizes she has been cheated:
You and papa have committed a great sin against me. It is your fault that I have made nothing of my life.
Had this not happened, Nora would have continued to operate like a robot. Now, however, she can learn to know herself and find value beyond how she pleases others. It would be a travesty to spend her life having so sense of self—something that doesn't concern Torvald at all.