Baldry said:
A'right yeah it was meant to be Anakin but after he betrayed the Jedi I consider Luke to be the chosen one as he brings balance to the force but you could argue since it was Vader that throws Darth Sideous to his doom he was always the chosen one, but without the existence of Luke he never would've betrayed his master so its arguable who truly was the chosen one.
And without Obi-Wan Luke would never have become a Jedi.
Luke just brought him back to the path he was meant to take. One might even say that Luke was just another teacher.
Oh, and Vader was going to betray Sidious one way or the other, the sith are kinda big on that. And he said so.