I always thought of Moffat as a brilliant writer / director, and his abilities took the show to a whole different level. Except for the few sexist instances (such as turning Irene Adler into a dominatrix, and essentially changing her complete characteristics from the canon), I barely noticed much of his tendencies and flaws towards writing women, and I still think he did a great job with Amy Pond, River Song and I'd confess I fell in love with Clara Oswald in her first appearance at Asylum of the Daleks (though that could be because I'm a man, and hence I'm not aware of it -- which probably explains why he wasn't aware of what he was doing either -- so I'd appreciate if you could open my eyes here). But from what you've said just now, looks like writing women is Moffat's kryptonite after all!
So in that sense, if one is to believe that Moffat has run the series into the ground with his sexism, then there's no way to go but up in this case. Writing the Doctor as a woman this time would give him the opportunity to overcome his kryptonite, and hence essentially grow as an artist. So in that sense, I think the fact that he's trying something new and different should be appreciated
because this may open plenty of doors. If he succeeds, it not only benefits him but also the audience.
If he fails, well... Doctor Who is doomed. And so is Moffat's career.
But then again, the failure may not only be at his hands here. I've read some Youtube comments before where some fans showed concerns about a female Doctor, saying that they'd quit the show if this was the case. In other words, Moffat would not only need to work twice as hard but four-times as much in order to keep the show alive, simply because some of the audiences are biased puppies.
So here, I'm just holding on to hope.