Vettori seems rather low on confidence. Before this most recent Test he's gone five innings without taking a wicket, which incidentally coi-incided with his batting suddenly improving and him scoring a hundred!
He was trying to pitch in the footmarks,and it was undoubtedly turning a lot, but he's quite capable of turning it of the flat anyway, as he proved in this Test too. But it was a bit odd. NZ
weren't going to stop England getting the runs, they had to bowl them out, and Hussain kept kicking him away. One or two of the commentators were pointing out the irony of Vettori using that tactic to get out the man who pretty much invented it.
But you're right about Giles spinning proclivities. As I said before though, if you have a spinner who moves the ball less than the seam bowlers, what else can he do? That was actually a typically shrewd Hussain move: "Right, our only spinner can't get the ball to move on a minefield, so what do we do?", boring to watch as it clearly was.
As for his average, I wouldn't criticise him. It's just that in future years those who never saw him may wonder why he's held in such high regard.
She's as nervous as a very small nun at a penguin shoot.