I would not put too much stock in the outfit. Recall they released pictures of Peter Capaldi in that dramatic black coat with the red lining, but Capaldi ended up wearing a lot of different outfits (hoodies!) during his tenure and was not stuck in one outfit the whole time. I hope they will allow Whittaker to change her clothes, because the outfit in the photo looks kind of mismatched and thrown together, rather than a pulled-together look. Of course, it might look thrown together on purpose, like maybe The Doctor doesn't know how to dress like a woman and just grabbed whatever fit...or sort of fit...out of the infamous TARDIS wardrobe. A duster like that will not photograph well when doing all the running they do on the show.
Pity she had to steal Laura Ingalls's shoes.