The point that Dawkins is making is that natural selection reduces massive improbabilities by sub-dividing them into smaller and more manageable improbabilities.
There are three intellectual blind spots that are characteristic of Dawkins’ rhetoric in his book:
Firstly, Dawkins seems to replace one explanation of gaps (God) for another (luck), which amounts to an intellectual ‘bait and switch’;
Secondly, it replicates a way of argument that has dogged the Intelligent Design movement – that the greater improbability of A must mean B is true, which is of course logically slipshod;
Thirdly, Dawkins assumes that a theist cannot agree with gradual evolutionary change, which produces false dichotomy where a spectrum of opinion exists. (Dan this is where I contend Dawkins makes a flawed pre-siupposition that makes further debate of his points superflous).