I don't like being wrong, but I'm human and it comes with the territory. It is rare that rumors are true, but twice this year they have proven true and proven me wrong. The more recent was right here on my blog. The rumor was that John Hurt was playing Doctor 8.5 (meaning between 8 and 9). I was insistent that this did not have to be the case, but as it turned out, it was exactly correct.
I'm a writer and I tend to think of an array of possibilities and I found that rumor to be the least likely. However, after watching the two Doctor Who specials in the last two months, that really is the only way this story could have been told. I can only guess where or when Moffat got the idea, but how things worked were chance just a few years ago.
When David Tennant's Doctor almost regenerated four years ago, I'm sure we all hoped that didn't count against the regeneration limit we all knew was approaching. But when you rewatch that episode, there really is no other conclusion. Then Christopher Eccleston declined to be in the 50th Anniversary special. That left Steven Moffat with a whole to fill, followed very shortly by Matt Smith stepping down from the role. We all knew Trenzalore was coming, though we didn't really know what it signified. The hints were that it would be Matt Smith's last episode (what else could "fall of the eleventh" mean). Then we were there early (or late from Trenzalore's perpsective) in The Name of the Doctor. The Tardis window cracked on landing and the giant Tardis had the exact same crack. Clara jumped into the Doctor's timestream and saw 11 faces. It has taken a while for that to sink in. From that point we knew the Trenzalore was where this Doctor would fall and it would be the end of the line. There was a missing regeneration and we had to wait until the Anniversary to find out that the Doctor we know so well did not fit in the Time War, so he had a regeneration dedicated to fighting and ending it. This incarnation did something so terrible that his later selves buried the memories and pretended he didn't exist. The Time War is locked so no one would know there had been another Doctor. But the terrible thing he had done turns out to be an illusions. He intended to do it, but he and two of his future selves found a way around it leaving Gallifrey hidden. Then we come to Trenzalore, the Doctor's final battle. When you take Eleven and add in the forgotten Doctor and the wasted regeneration, this, the twelfth incarnation of the Doctor, is the last. Except the Timelords have their own tricks to fix things. A whole new life cycle. The pieces all fall into place and it is so fitting that the Doctor ends his first life cycle at the 50th Anniversary and starts a new one.
So while I could think of many alternate explanations for John Hurt's Doctor, and many ways to preserve the familiar sequence, what Steven Moffat has done is genius. We couldn't have asked for a better way to celebrate 50 years and say goodbye to Matt Smith's Eleventh Doctor. And it all hinged on a wasted regeneration and Christopher Eccleston not participating. It was so obvious that he was new to the face in Rose and it would have been another glitch to have him play the Doctor who fought in the Time War. We have enough of those with the Second Doctor's several returns.
So all in all, I am glad I was wrong. I think the story has turned out just as it should. Still, it is fun to imagine the other possibilities.