There are a number of options available to the theologian who wants to refute Dawkins position. First, she can simply place God outside the rules of causality and grant God the ability to do things which look contradictory and impossible from the human position. This isn't actually particularly absurd, it simply places humanity in a position, like that of the shapes in Edwin Abbots Flatland, where something routine to a 'higher being' is practically inconceivable to us.
She can also grant the "many universes" hypothesis. In that case, everything that God considers happens. So somewhere there is a universe without humanity, and somewhere there is a universe where humanity is not destroyed by beings from Sirius III in 2050 because God sends them a horrible plague of rats. In that case, God can intervene back in time, forward in time, change his mind and intervene again... because everything just creates new timelines.
Of the two routes, I think that the first is the more compelling. It actually makes sense to say that you can't use human concepts of space, time, foreknowledge, and causality to meaningfully discuss the traits of a being that supposedly knows the precise position and velocity of every particle in the universe, since that knowledge alone violates everything we understand about space, time, causality and particles.
To clarify this answer somewhat, the problem with Dawkins' logic is that the premise actually denies the possibility of a logical conclusion. An omnipotent being is without limits by definition, so the imposition of logical limits on the being is a denial of the premise, not the conclusion.
The inconsistency of Christianity is not in the assertion of an omnipotent, omniscient being, it is with the insistence that such a being could be said to have motives or behavior that would be even remotely comprehensible to us. If we assume a god on that scale, the conversation must end there: we cannot divine that beings motives or desires or even say that it has any motives or desires that we would understand as such.
In other words, the problem with the Christian god is that Omnibenevolence is logically inconsistent with Omniscience and Omnipotence. An analogy that might be helpful is the idea of a computer programmer. Let us assume I write a game like the Sims in order to play it. The game is large enough that I can have multiple villages of sim creatures. I might encourage them to go to war with each other just because I want to see them go to war. I might give them competing religions just because I think its funny. I might do absolutely anything, for any reason.
To the Sim people, none of this would make any sense. In fact, from my point of view, a Sim lacks the capacity to even have things make sense or not make sense. From my point of view, a sim has no thoughts or feelings that I would recognize as such. They are just simple robots. And from their point of view (assuming they have a point of view), I am utterly beyond comprehension.
To a truly all powerful god, we would be simpler by far than a Sim. We would have less capacity for self direction, less capacity for self awareness, and less capacity for intellectual thought than a computer program. There is just no way for us to intuit the motives or desires of a being that is that much more powerful and intelligent than we are, and no reason to believe that such a being would ever give us directions that were to our own benefit in any way. God could be totally ethical from its own point of view and still lie to us constantly, because it just isn't unethical to lie to creatures who can't think or feel.