Hmm, i really don't know how the hell i'm going to critique a 3d image...
I imagine is not rendered yet right?
Her pose looks very natural, but i think you could make her left hand have a more firm hold in her leg, it feels a bit loose.
And i guess for this pose, the shoulders should be down instead of up? you know, since she is stretching her arms to hold her leg, it would be not confortable to do that while raising the shoulders.
Now, to contribute to this a bit more, some pics that i've found.
This really cool and awesome Mila fanart:
Source
And this really cool Ayane Fanart
Source
And also, more self promotion, yay, this time, Nyotengu.