He is never going to do the origin for the same reason he is never going to do the time war nor neither reveal the Doctor's name - it is always going to be a disappointment.
I agree with 2 out of the 3. I think a true origin story that shows why and how the Hartnell Doctor stole the TARDIS and left Gallifrey could be a great story. Sometimes you have to swing big. But, that's a defining moment for the character that's ripe for telling.
I don't think that's what we'll get for the Anniversary special though, and that's OK. One of my favorite bits of the season finale was seeing Hartnell and Susan steal the TARDIS!