@Buzz is it really that off? Seems like his balance is OK and his head is in the right position. Bottom hand not too strong (otherwise he would be turning the bat to leg) and weight going nicely through...no?
Yes, head position, balance and timing are impeccable. Which is why it works, his bottom hand grip is horrible, but it seems to be a trend to hold the bat like that these days, Hales and Roy also hold the bat like that.
Might explain why Hales struggled at test match level.
Smith's head position is better than Hales and he is more fluid and less stiff than Hales too, in my view