To me, the arc of Anakin is very well done.
Force sensitive beings were taken as soon as birth or as young as three. Anakin was nine when he started training in the ways of the force. He knows hate, love, passion, ignorance, chaos, jealousy because he was raised as a normal slave boy. Jedi younglings are more like cult children. One way, conformity. Taught from birth the Jedi Code.
They know no love, passion, jealously because there earliest memories are this code that they forcefully live there lives buy and are trained to uphold this code since there first moments as a living being.
Anakin has these emotions already. He can not be taught to control them at this age. Sure, TPM goes long on the pod race, but finding Anakin and learning that he has a mom, is a slave, the emotions are there of love and hate, passion and jealousy. Paths to the dark side are planted in this young boy from an early age. Then he has to leave the only person he ever loved, his mother, not letting her come with him, small patches of hate toward the jedi in that reason alone start to grow in young Ani.
Fast forward to AOTC. A teenage Anakin. The death of his mother, slaughtering the Tusken Raider men, women and children even. The emotions carry over from TPM to AOTC, he never could control his emotions. Throw in the love of Padme, it clouds his judgement, even his love for Obi-Wan clouds his judgement in the rescue mission for him on Geonosis, that and his willingness to please/protect/do anything for Padme. He marries Padme and vows to basically do anyting to protect her.
Fast forward to ROTS. The constant badgering of Palpatine slowly manipulating this emotionally unstable young adult. Killing Dooku, worrying about the fate of Padme, the same fate of his mother, that she could die. Do you see how AOTC is connected to ROTS. The inability to stop death has warped his mind throughout that time span to the point in his mind everything he does is to save Padme, which was saving Palpatine, killing hundreds of Jedi and Jedi youngling. All for Padme. Of course it his eagerness to save Padme which ultimately kills her, to me completing the transformation.