He's got some damn impressive numbers in his last two seasons of Pura Cup. Last year he took 40 wickets @ around 20, and he's on target to do likewise this Summer. However, in my view, the selectors are looking for the 'nip' (that extra 5kms of pace) to return to his bowling. That was what was lacking in Ashes 2005, and regardless of his numbers, he won't break back into International cricket on a consistent basis until the selectors think that the 'nip' has returned.
And, when you're on the wrong side of 30, the 'nip' rarely returns. Having said all that, Dizzy's best chance of a recall is next Summer against India - if the Aussie pacemen fare as poorly as they did last time India were out here against an Australian side sans Warne and McGrath, then they must just look for a steady, experienced hand on the tiller.