Not so much a transformation as it would be a complete subversion of a person's humanity. But you have the gist, yes.

Human will is capricious and imperfect. We have no objective measurement of what is 'correct' beyond what we can rationalize at any given point in time. Remedies to mental health are usually done along the guidelines of making an individual's behavior more amicable to society at large, but that in itself is no Northern Star, either.

Be that as it may, any individual that had the power to completely re-make themselves into their 'perfect' self would eventually annihilate themselves. They would see something new in their behavior that would displease them every single day, something that could be 'improved' out of sheer hedonism. An act of spiritual cannibalism until nothing would be left.

Forgiveness is the path to free oneself, whether that be from Sin or Samsara.