Which isn't to say it's as desperately original as Miles seems to think it is. The whole thing comes across to me as really very Glorious Dead -- cloaked religious zealots who turn out to be a corrupted humanity from a "wrong" history of Earth and so on -- though mining the DWM strip seems practically obligatory for the new series. (From, erm, the same strip, actually, the Doctor to the Master: "You destroy the history of my favourite world, turn its people into religious psychopaths, seduce my TARDIS ... You're really trying to get me angry, aren't you?" End of S3 much?) And any treatment of infinite libraries by Miles, Moffat, or anyone else is always going to owe a huge debt to Borges (at least Dave Langford acknowledged it directly).
Nor is it to say that it would necessarily work as a "new pilot episode". As someone peeeeeeet pointed out it would be very effects-heavy, which could be a risk -- though the sort of things Miles uses are the sort of things that I think the Mill have tended to show they're good at -- I'm thinking of some of the New Earth stuff in particular as being along similar lines. Also, I think the youth of the companions is a bad idea. Doctor Who is supposed to appeal to kids, but I'm not sure that these guys would. (I'm sure I read something somewhere once that said that children prefer protagonists a little older than them.) And there's so much risk of them turning out to be annoying.
The stuff about hiding contemporary Earth as the Book is particularly interesting on both the originality and reboot fronts. The idea that OUR period of history is somehow particularly important is not a new one from Miles, despite his protestations that he wasn't going to reuse stuff; it seems to me to go straight to all the ghost point stuff from the Book of the War and This Town ... (my True Nature of the Enemy theories, let me show you them). There's also the rather heavy-handed declaration that the series following on from this is not not not going to be going anywhere near contemporary Earth. It comes across as very manifesto-ish, and in many ways the whole plot is bent around achieving this, but as much as I would like to see more of planet Zog I do think RTD has the right instinct when it comes to the several million people who watch the show regularly but aren't in fandom: they want stories in the mix that they can relate to, so never going to contemporary Earth would be a bad plan. (I don't think this is insulting to the intelligence of the audience, incidentally. It's about giving people eggs and bacon with their six impossible things.)
But as a new piece of writing by Lawrence Miles, I enjoyed it immensely. Certainly more than Body Politic which had fun stuff in it (particularly the bits set amongst the Great Houses) but was a bit of a mess overall. The Quiescence were properly scary even just in script form, and I like to think I don't scare that easily. The bits with the Doctor having been there for ages and the hidden TARDIS worked brilliantly (the use of the keeping count thing on "It's bigger on the inside ..." was particularly great).
And in general it turns out that damn, do I miss Miles writing for the Doctor. Here's hoping Moffat can look past all those deliberate-seeming bridge-burning attempts and bring him on board somehow. (My personal suspicion is that the biggest stumbling block is fucking Confidential and all the rest of the hideous promotional superstructure that I wish wasn't there -- you're not going to get Miles giving nice trite soundbites, are you?)