The ones that I'm skeptical on -- or rather, that I think are true but don't mean what Whistleblower seems to think they mean -- are the last two points, on big name writers and their scripts being dumped.
is a series that works with freelancers. Moffat writes five or six scripts out of 13 each season. That leaves seven or eight scripts for freelancers to write. Moffat isn't going to commission exactly
seven or eight scripts to fill his needs because then he'll be left short when a writer can't deliver. No, he'll commission nine or ten scripts from freelancers each year (after taking pitches for double that) so that he's not
left short. And then those extra scripts may be in the mix for the following season, as Neil Gaiman's "The Doctor's Wife" was (commissioned for series five, produced for series six).
So it's not at all unreasonable for Moffat to have commissioned scripts that haven't been made. And yes, spread across three seasons, that could total to eight completed scripts by now.
Now, there is a dark flipside to this.
Moffat has commissioned completed scripts when he himself has been unable to finish his own. Had Moffat's storytelling not been so arc heavy and his scripts the keystones/backbones of his seasons, those commissioned scripts would, in any other production, have been slotted in to replace what Moffat was unable to deliver himself.