I can think of only one story Hollywood execs would be interested in doing - a Secret Origin story that reveals the REAL reason One (who presumably would be played by David Bradley if he's still around by then) grabbed Susan and took off from Gallifrey.
There is an argument to be made that "The Doctor Begins" is exactly the sort of thing Hollywood would want. Not because they want (or prefer) "Secret Origin" stories, but because that's a story that the television series hasn't told, so the story itself becomes a point of differentiation from the television series and a reason to go to the theater to see it.
In light of the leaked email, I begin to wonder if "Listen" was Moffat's shot across BBC Worldwide's bow -- "If you even
think about a 'secret origin' movie, I'll beat you to it." That may be too Machiavellian for even Moffat, though.
The questions that Worldwide needs to answer are these -- What can a movie do that the television series cannot? How does this build the brand? And, more importantly, how does this complement the television series?
The television series can do
anything; a movie is going to be, pretty much, one type of story. (Which is why some of the 90s movie scripts, like Denny Martin Flinn's, attempted to shove all of the
Doctor Who genres in, shifting from pseudohistorical to space opera every ten minutes or so.) That's probably the biggest argument
against the film, and why the "Secret Origin" story would be compelling.
Casting David Bradley, however, would be a mistake. So too would be soup of Daleks, Cybermen, Weeping Angels, Time Lords, and Susan be. If the production team starts from the premise that they need to make a film for
Doctor Who fans, then they've already failed. The film needs to be as accessible to non-
Whovians as possible. Think "Rose" or "The Eleventh Hour," which were designed as "jumping on" points. Don't think the McGann film with its "kisses to the past."
In other words, the BBC needs a
reason, beyond a naked cash grab from fandom, for a
Doctor Who film. We've seen that the Marvel Universe can coexist on television and in film sharing a universe, but that's because each product is different.
Doctor Who is a wizard in a magic box; the lines may change, the options may be more high-tech, but functionally under the hood it's the same car. I'm not at all opposed to a film; indeed, I'd welcome a non-Moffat film if Moffat were still producing the series because I'd like to hear a different "voice." But there are certainly questions that need to be answered first. From his interviews at the time, it sounded to me like David Yates understood those questions and had pondered them hard. Hopefully, the next person attached to a
Doctor Who film understands them, too.