Darth Lucas said:
To me, Obi-Wan's character arc is fully explained in the OT. "You are reckless." "So was I, if you remember." Obi-Wan starts out as a kind of hot-headed jedi who lets his feelings get the better of him, similar to Luke running away from his training after getting the vision of Han and Leia. He jumps into training Anakin without much thought because he is emotionally attached to Anakin and wants him to succeed, without thinking of the consequences. Over the course of the story Obi-Wan shifts from the hot-headed young Jedi to the wise man we meet in ANH. How exactly that happens. Well I haven't completely worked that out yet.
I have something similar going on in my mine, though Obi-Wan is more of a deuteragonist with Anakin being the protagonist.
Kenobi has matured somewhat from his reckless youth, but there's still a thoughtlessness to him albeit surrounded by good intentions. He grows as the films go on, learning to consider and evaluate his decisions, but the tragedy is that his student remains his biggest blind spot. He takes on Anakin as a student without considering there may Jedi Masters who would be a better fit, allows himself to get blinded by how troubled Anakin is getting because of the progress the latter's made, and neglects some of his duties as a teacher because he's so focused on living up the example set by Yoda by acting as a leader to various Jedi.
He's an intelligent, moral, and loyal knight, but his short sided view on things proves to a real problem and is a source of emotional distance between them. Kenobi's demonstrations of value in believing in things like the Republic and trusting the in the light side of the force ultimately come across to Anakin as trusting in blind faith. And Skywalker internalizing and compartmentalizing so many of the traumas or troubled emotions is mistaken by Ben to be him being a strong jedi and rising above them.
Obi-Wan becomes a better leader and Jedi throughout the films, but never quite improves as a teacher until its too late.