4. Captain Jack Harkness
I don't know about you, but I've been waiting eagerly for Jack Harkness to make a return to Doctor Who. He almost did it in 'A Good Man Goes To War', but scheduling conflicts with Torchwood: Miracle Day made that difficult. With no more Torchwood seemingly on the horizon, let's get him back on the show he first came from. I've also been waiting for a scene between River Song and Jack Harkness. The banter and innuendo would be electric. (Apparently this is something Alex Kingston and John Barrowman were quite vocal about when they were working together on Arrow). I always imagined that Jack would be a kind of recurring character...a sort of modern Brigadier. I think it's a shame we won't see him with Doctor Eleven, as they would have played well off each other. (Unless he makes a surprise appearance in the 50th special.) Jack was always more fun when he was back in Doctor Who. I have no problem with character development...but in the choice between gritty, serious Jack and rebellious, fun Jack, I prefer the latter. Jack is an ally that spanned two Doctors. There's no reason why he can't span three. There's the potential for Jack to reoccur for years to come (like River Song). Not to mention the fact that Moffat wrote him first in 'The Empty Child' / 'The Doctor Dances'. It's about to time Moffat's fantastic storytelling and Barrowman's magic converged on screen once more.