2. The Other Eight Doctors
This ones a bit crazy, but I think it would be amazing to watch Billies acting in this. It has been said that none of the older Doctors were a part of filming the Fiftieth Anniversary. Only Peter Davison (and very, very recently Tom Baker) has come out and said that he was doing something that was a part of it and I dont even know if thats true. There have been more speculation about Doctors and a mini-sode starring Paul McGann, but what if because of the Time Vortex and everything Rose saw, she played the Doctors? This would be a Moffat-esque loophole 'No, the other seven doctors arent in the episode, theyre played through Billie Piper.' I dont have much of a theory to back this up, but I can imagine that the TARDIS would, again, call on everyone she knew to help Eleven in what hes about to face including past regenerations. Because three of the actors that played the Doctor have died it would be stunning and a tad weird if they were played through Rose. Not only would this be something that Moffat would come up with, it would really show off Billies acting. Could she convincingly play a number different Doctors, ones she wasnt alive to watch, and then play them in a way that would allow the viewer to know which one she was playing? It would be easy for Tennant to do this, maybe even Smith (he's done it before in The Almost People), but giving it to Rose would be a genius. No-one would see it coming, and it would also allow for a look back at the Doctors in a way that could help the plot along without having to deal with finding someone new to play the first three Doctors. Is it far fetched? Possibly. But the more I write about this, the more I want to see it.