I watched her a few times now, and... No...
Sorry, but No.
Too young and could as well be a companion with those looks. She looks too.. bland too... conservative and "cute". She is so unthreathening to the male and seems too have very little substance doctor wise. Mind you I can be pleasantly surprised, Matt Smith surprised me majorly as well. Didn't like him at first either... but grew on me.
But my first impression: Why choose something so bland with all the fantastic women out there that could have played the role. The genius that was "Missy", someone that scared you while basically recasting the Master... Brilliant! And that is my main issue, she is too.. human....
Again, like Matt Smith, she has time to add the quirks of being Alien and odd. But I would have loved for some woman with Authority in there, someone that doesn't fit the conservative ideals of beauty (Blond, Skinny, White)..
And yes, I know that criticism on the choice ... but I keep asking my self:
Why not Black? Why not less fitting to the imposed ideals of beauty? Why not Asian? Why not... etc.
Sigh... I just hope she'll grow on me, and is a hellraiser in disguise
.
At least it is one step in an interesting direction, so that's good. Another "young man" (with the exception of Capaldi) would have been even more boring.