From The Telegraph:
Versatility will therefore be the key ingredient. If you bowl first you will need loads of spinners to take advantage of the dry pitches that will prevail at the end of the season; if you bowl second you will need loads of seamers to take advantage of damp pitches, or at least medium-pacers who control a dewy ball, not fast and furious siege-engines like Shaun Tait who could spray it anywhere.
And it so happens that the three host nations have selected this appropriate mix of seamers and spinners, including batsmen who can bowl part-time spin – unlike Australia who have picked one spinner in their squad, Nathan Hauritz, who badly damaged his bowling shoulder in Friday’s win over England in Hobart.