You don't have to rewrite them at all, though, because of the strong (canonical) foreshadowing that the Doctor is someone older and more than just the Doctor. (Which was sort of a given, whatever they said about Timelord reproduction.) Is Susan a bit pushed-and-pulled to fit, by making her the Other's granddaughter? A bit, yes, and that's largely why I don't advocate it personally, because I don't know how literally I want to think that the Doctor equals the Other - if you take it very literally, it works, if you don't, not so much. But nothing in any version of that says that Gallifreyans don't fall in love with Aztec or Sevateem chicks - in fact, it very specifically says it was a technological response to infertility, which strongly implies that they do. And it's a perfectly good supporting reason for why Gallifrey has no one under the age of 25 living on it, why there's so very little reference to family, why the Doctor makes cracks about having been born under the sign of "crossed computers", why they're so blase about the old looking young and the young looking old, why the Sisterhood of Karn is so closely related (and needs other ways of staying young).