Given the fact that Shelley wrote Frankenstein based upon a challenge placed by her husband and other writers, one could be sure that she was proud of the monster she had created. Mary Shelley was the only female writer in the room when the challenge was laid down, and she was the only one who created a story so horrifying that her husband pushed her to finish the story. As for the text itself, readers could interpret Shelley's interest in the monster best from the chapters written from the monster's perspective. It is here that Shelley seems to relate her compassion for the monster. In the chapters written from the monster's perspective, the monster is shown as compassionate, concerned, and empathetic. Given that most monsters are not written into texts in this way, it could be interpreted that Shelley had the same feelings for her monster.
While nobody really knows this but Mary Shelley, I can give you my opinion based upon her biographical information. Shelley felt the creature was basically a good soul placed in an environment that brought out his evil.
Shelley was raised in a philosophical, forward thinking family. She was kept abreast on current thought in a variety of disciplines including medicine, psychology, philosophy, religion and even feminism. Her basic conclusion, which her mother shared, was in the intrinsic goodness of human beings.
She shows this in the novel by presenting the creature as inherently good. His early years reveal him to be caring, empathetic and even nurturing. He feels for the De Lacey's as they suffer through exile and poverty and nurtures them by helping them with physical chores. Even after their rejection of him, he still finds cause to rescue a young girl from drowning. Basically, these drives toward goodness show that in another place, another time, and with different treatment, the creature would have never resorted to murder.