Daniel Vettori is like the AWs Ivan Vicelich. Even though he is largely done at that level, he is still the best in his position.
He can still do a job at test level in this unique situation and should be able to handle the bowling workload given he will share it with 2 other spinners. We do lack a bowler such as Astle, McMillian or Ryder who can bowl tight probing delivers at 110kmh and that hold up on some surfaces and swing very late. Maybe a job for one the batsmen to work on?