The idea of 'sacrifice wicket' is totally unacceptable. The way Redmond's gone replacing him with any batsman should yield better results. Haven't NZ got anyone? What about guys like Broom, or Guptil or Anderson?
We've tried that theory. Bracewell argued that your best batsman should play, regardless of their batting preference. Hamish Marshall and Peter Fulton were subsequently tried, and failed, putting that theory to rest.
There are no back up openers in the squad, and frankly there are no openers who are good enough to succeed in Australia at the current time, nor any player good enough to successfully make the middle-order to opener transition.
Guptill is actually an opener though, and one of few who should be considered for our home Tests.
I'd hunt Bracewell down and give him a a good kicking if he picked Anderson to open now, or Broom for that matter.
Redmond has gotten used to Australian conditions slightly, and actually has some cricket behind him. All the other options have only just started in our Domestic season at home, and those who have had experience of Australian conditions (just Bell IIRC) don't deserve to be called up.
So, in short, I don't think it's worth calling up someone who hasn't really earned it for a single Test against the best team in one of the hardest countries to play in.