How would Journey's End have looked if the tenth doctor had regenerated?

I have continued to think about the last episode of this series of Doctor Who, Journey's End, helped along by the usual dose of podcasts and online reviews. I have to admit that unlike the best episodes of Doctor Who, I mean the really great episodes, it does not bear too much thinking about, and the element that consistently niggles is the extraordinary business with the second doctor, the "Odd Job Junior Doctor" as I called him in my review. It's just such a bizarre idea; why on earth did Russell T. Davies come up with such an extraordinarily weird idea as having a duplicate doctor growing from that hand in a jar? Well, today I caught up with the Tin Dog Podcast, one of my favourites, and its presenter (Michael?) had a theory so good that I think it might be right. Of course I encourage you to go and listen to the podcast, but the gist of it was to imagine that at the beginning of "Journey's End", the tenth doctor had regenerated into the eleventh doctor, and then, later in the episode, that hand generates the tenth doctor clone, as we saw in the episode. We then have a two-doctor episode, tenth and eleventh, with the eleventh the "real" doctor and the tenth doing everything we saw him do, with Donna et al. Now imagine the scene in Bad Wolf Bay at the end. We have the eleventh doctor, a new face, played by who knows? (I like to imagine Richard E. Grant) and he is not quite the real doctor to Rose, not her doctor. And he fudges the crucial moment at which he could say what he had said at the end of series 2. And then the tenth doctor clone, who looks and feels like her doctor, is able to say those crucial three words in her ear, and Rose is happy to go off with him. Just imagine the feel of that -- it would have been perfect: Rose is united with her doctor, while the new doctor, still unfamiliar to us all, goes off in his TARDIS. What a fantastic way of creating a transition between the doctors that would have been! What an end of an era!

Most of the above is from the Tin Dog Podcast, though some is my own riffing on the theme. But I can't help wondering whether Tin Dog is actually onto something here. We know that Russell T. Davies likes those sorts of perfect tie-ups -- we saw it at the end of the second series, with the alternative universe's Pete Tyler joining up with our universe's Jacky. And bear in mind that David Tennant was always rumoured to have been standing down at the end of this series. Catherine Tate leaked this before the series had begun, to the evident annoyance of David Tennant himself, and perhaps that was the original deal. Russell writes the final episode with the regeneration to cap them all, a cliffhanger at the end of the twelfth episode, and a clever means to keep Tennant involved right to the end. I think I could easily have coped with Rose going off with her Tennant doctor at the end of the episode, not quite sure what to make of the new incarnation of the doctor who is now about to begin his new adventures in the four specials.

If this scenario is right, and it has some considerable explanatory power, we will probably never know until Russell writes his memoirs, and even then he might be guarded. Or perhaps one day David Tennant will tell all. Perhaps Tennant could just not resist the temptation to continue doing Doctor Who for a bit longer, to become the definitive doctor, to trump Tom Baker's tenure (three more years will do it). If it is right, I suspect that Russell liked his plot too much, and adapted it so that it would still work with Tennant playing both characters, though I think this may have been a mistake. Perhaps someone should have said, "Come on, Russell, this doesn't quite work" but there was no one to do that. Let's hope Steven Moffat gets a script editor who can say to him, "No, Steven, I don't think so" from time to time.

All the above is probably complete rubbish, but it's great fun to talk rubbish from time to time.