Key only replaced Butcher because Butcher was injured, it's not Key's place.
I think Vaughan should move up to 3 and Pietersen should bat at 4.
I agree that form is temporary and class is permanent, but at the moment, Pietersen is class. How did anyone come to know that Trescothick or Vaughan were class?... after watching stretches of excellent form.
Butcher does have a high average in the last few years. He is an example of why I don't think a batsman's average is a true representation of his ability and value.
I believe an average is more reflective of how big a batsman's big scores are, than how often he can be relied upon to make a good score. This was the case with Trescothick on the South Africa tour. His 180 gave him a series average of nearly 45, when in fact he had a pretty poor tour.
As far as I'm concerned, the frequency with which a batsman does not fail (i.e. scoring less than 25) is of more value to the team than whether his big score was 180 instead of 130.
A batsman that does not fail - does not give his wicket away cheaply, is more valuable, as he will get himself played in more often and will give himself a much better chance of making that big score 9e.g. Pietersen in the OD series).
Again Trescothick is an example, this time in the one-day series consistantly getting himself out early. If he'd made 150 in one of the matches, his average would have looked a lot better, but he'd still have had a poor series.