I do see what you're saying about Time Lord's possibly having different concepts of gender (and I stand corrected on The Doctor's Wife!), but it still seems to me that the Time Lord's do identify as male or female enough that they want their biological sex to match that. The Master becoming "Missy" seems IMO to be a pretty big aberration, rather than something that they're all clearly comfortable with doing all the time, as the other Time Lord's have all made a point of sticking with their preferred gender everytime they regenerate. That's why I'm not sure how much sense it would make within the show for the Doctor to regenerate as a woman, even with Missy setting precedence for it

I'm not all up in arms about it though I feel I should add! A lot of people who are against a female Doctor give that side of the debate a really bad name I know :P But yeah, I'm just not sure that it would work for me with how the Doctor's character has been established as having always been male. For a film franchise reboot sure, but for a character to actually switch from male to female on a tv show as part of the continuity is what I'm not sure of I guess. They pulled it off with Missy beautifully, but I'm still not at the stage of clamouring for an actress to be considered for the Doctor's next regeneration

On the other hand, I'd also be very happy if they brought back Romana or Susan or the Rani or even Jenny, so that we'd have a mostly-female-identified Time Lord around.

I agree with that :)