6. The Return Of Rose Tyler
This one might draw a lot of venom from certain fans but it's interesting to speculate nonetheless. Rose Tyler was the first companion the Doctor had upon the show getting its renewed run in 2005. Before she met the Doctor, she was just a simple shop assistant in London who later became stuck in a parallel dimension with a human copy of the Tenth Doctor - to cut a
very long story short! Who's to say that if/when Gallifrey came back to normal space, it didn't bring a few things with it as well, such as a certain companion of the Doctor that he had grown particularly attached to? Would the current Doctor feel that same attachment to her or would he even be happy to see her anymore? Would she continue to travel with him or has she made her life complete having "her Doctor" with her at all times? It would be interesting to find out.