OK, one more thing about Cold Blood. If Rory has been wiped from the time stream so he never existed he wouldn't have been there to take a bullet for the Doctor and the Doctor would have been dead and Rory still alive. You can't take a character out of a story, retrospectively- as if you were excising an appendix- and have everything else remain the same. If Rory hadn't been around the Doctor wouldn't have had any reason to resist Amy when she tried to snog him and they wouldn't have gone on that "honeymoon trip" to Venice and- basically- nothing we've seen in this season so far would have happened the way it did. Moffat plays with clever SF tropes, but doesn't think them through. There are no rules in his universe.
Oh, and another thing; how come Rory was obliterated by whatever it is that comes out of the crack, but the Doctor could stick his hand in it and not be hurt at all?
RTD used to get his characters into situations where only the magic button would save them- which is another way of offending against the decencies of SF- but I don't remember him dicking about with the logic of his imagined worlds the way Moffat does.