They might have called Doctor Who a "comedy soap opera" earlier this week, but we’ll forgive io9 that indiscretion as they have a bonza interview with future showrunner Steven Moffat online right now.
It would be churlish to reveal all here, so I won’t. What I will do is encourage you to go and read it – Moffat reveals a lot without actually saying anything or giving any hints even.
However if you haven’t got time to exercise your left mouse button, read this, an answer to the question of change and the connection the Doctor has with his companions familes:
You change everything, all the time. Even that element of the show has changed radically over the past four years… You don’t worry about doing things radically, in an a new way… [You] do what tells the story… It was very important that Rose, Jackie and Mickey were clear, developed characters.
[When the show started] the Doctor was a ridiculous guide. [Audiences didn't] understand who he is and what he’s supposed to be. But [now] it’s very different, because the Doctor is the most familiar character in the show. [Originally] we knew Rose much better than the Doctor, and now we know the Doctor better than we know Rose. And now we see Rose from the Doctor’s point of view, instead of seeing the Doctor from Rose’s point of view. You have to stay alive and stay lively, and Doctor Who is about change. Change is part of Doctor Who‘s formula. It must change.