A Healthy Skepticism
As a long time Doctor Who fan, I remember being one of the skeptics back in the age of Matt Smith. "There can't be another regeneration! Matt Smith is the last one!" We did the number, we argued, we cried, we wept in the ashes all the way up until Moffat created a perfect excuse for there to be yet another regen.
Now, the question "how many regens are there now" is even being asked by the Doctor.
While we were taken aback during the last season of the Smith saga, is it possible that we may have been given a hint that this was coming as far back as the David Tennant era?! I believe that this is entirely the case, and I think it lies within the prophecies of the Ood.
Species of Time
Throughout all of the Tennant series, the Ood have kept popping up and having significant roles in the foreshadowing of the Doctor's life. From Rose's "death" to Rose's return to the death of Tennant, the Ood have been actively seeing into time and speaking the warnings of the universe. But not all that the Ood have spoken have been doom and gloom. They sing and speak life as well.
The Ood, unlike most species, were able to see into time and to even project their image out across space and time to wherever the Doctor was to speak to him and share their visions with him. With that said, let's look more closely at the Ood at the end of Tennant's regeneration.
In the Tennant specials, we saw Ood Sigma reach out to the Doctor across time and summon him and speak prophecies to him about the end of his time. Now, what is significant here is that the predictions are always accurate. They happen exactly as they say they will, down to Wilfred knocking four times at the time of the Doctor's next regeneration.
As Tennant is making his final crawl to the TARDIS to begin the next regeneration, Ood Sigma appears to him one last time to let him hear the Ood "sing him to sleep" through time.
As Tennant enters the Tardis, Ood Sigma speaks one last time. Not looking at the screen, but potentially breaking the fourth wall to speak to the audience, Ood Sigma states, "This song is ending but the story never ends."
The story never ends!
Is this the Ood telling all of us in our moment of sorrow, believing that we were seeing the beginning of the last regeneration, that there was more yet to come down the road?!
Taking into account the role that the Ood have taken thus far in the story as powerful seers and the accuracy of their predictions, it would behoove us to give some credence to this small line.
Especially since Ood Sigma isn't talking to the Doctor since he is out of earshot, it is more than acceptable to believe that this is a line being stated for us, to us, and because of us. If it is, in fact, a true fourth wall break then it is definitely Ood Sigma telling us not to fret over the alleged "last regen" of Matt Smith, but that there is more yet to come and this could mean that Whittaker isn't the last one either.
It will be interesting to see if the Ood ever return or how the writers will develop this particular element of the story since we are now two regenerations past the traditional limit. This also leaves hope that one day we may yet see a ginger Doctor!
Only time will tell...