So, Doctor Who's a chameleon of a show. That's its Raison d'etre under Moffat; it will jump around and imitate all sorts of things in a schizoid fashion. And one of the biggest things Doctor Who has never really intersected with is the Prime Suspect style of show. Long stories where you know the villain and state of play at the start of it, and the pleasure is in watching the lead actor work through it. And where that very open perspective is contrasted with an emotional drama. So we have a story in which the mystery plot is one in which we watch the main character come to a conclusion we already know, but the emotional plot is one where we and the main character move along together. Luther is similar, but with a clever twist in the form of Alice Morgan, who plays the Irene Adler sort of role of simultaneously being a villain and a romantic interest. And so every episode (for the first season at least) the crime plot unfolds completely open whereas the emotional plot plays dangerously closed.
The open approach is a structure that works trickily with Doctor Who, because it needs some equivalent of a crime. And Doctor Who doesn't quite do crimes. (Nor does Sherlock, apparently - Series 2 has exactly zero episodes about Sherlock solving a crime.) Typically it's only possible to do that sort of open storytelling with a baroque alien invasion plot. So, for instance, in The Bells of Saint John we know who the bad guys are and what they're doing, but we build a mystery around why, since their plan is horribly over-elaborate. But it's hard to build an emotional plot around that, since having the Doctor fall in love with the femme fatale is just jarring and a bad idea. (Unless it's the Master.)
All of which is just to say that this is, structurally, how to understand the River Song story. It's an attempt to find a way to the Luther plot structure in Doctor Who. So instead of a crime we have a time-wime. But we and the Doctor still both know who did it: River Song. But River, like Alice Morgan and Irene Adler, is also a love interest. And since it's not strictly speaking a crime but a time-wime, there's no obligation that River be villainous. So she can fulfill the emotional structure of the femme fatale - the hero loves someone who's guilty - without actually getting into the messy bits of that trope.
And now that we see that Doctor Who and Luther were cross-polinating, we can see where Moffat got the basic structure and approach from. (Tellingly, the first post-Luther episode of Doctor Who is The Impossible Astronaut/The Day of the Moon, which is where the River Song story veers most blatantly towards the Prime Suspect/Luther format, to the point of actually having a murder to solve.)
In any case, if the Kickstarter gets to $10k before Wednesday, I'll post the Rose update - a 13,000 word beast that I'm phenomenally proud of - as a backer-exclusive update. That means anyone who has donated, even a little bit, gets to see it early. So please, consider even the low-end contributions like the $5 ebook, or even the $1 backer-exclusive essay (likely to be Big Finish's recently-announced The Beginning).
Also, we hit $7,000, which means the Logopolis Choose Your Own Adventure-style book is happening. That's available for pre-order via Kickstarter by adding $15 to any existing pledge level. ($20 if you're not in the US.) And right now we're stretching towards making some merchandise like prints and t-shirts out of James Taylor's fabulous cover designs.