I can’t speak for Ann Gauger, or Mike Behe, or “ID” as if it has a unified position on theological questions. I can only give my own view.
It might well be that God would create a world in which there were certain harmful things, but in which there was an overall ecology that was good.
There is a tendency among some creationists to read “very good” in Genesis 1 as meaning: “All very sweet and nice, without any discomfort, inconvenience or difficulty of any kind.” I can understand this tendency, since many of the mythologies of the world refer to a “Golden Age” in which, it is imagined, everything is blissful for human beings, and often for all sentient beings as well. But I don’t think it’s safe to assume that Genesis 1 has the same teaching as those other stories. Therefore, I think one should be careful not to milk the phrase “very good” for more than what it was intended to convey.
Could God have willed the existence of destructive creatures? Well, we know that God sometimes creates evil (Isaiah 45). Such statements tend to be ignored by YECs and TEs alike, where OECs and ID people tend to take them more seriously. We also know from Job (where the discussion seems to be about created nature, not “fallen nature”) that predation is part of the order of things. And diseases, while horrible, can conceivably in some circumstances do good. I think the world would have been better off if Hitler had died of some disease before he began the bombing of England or the invasion of Russia, and if he had, at least some Christians would have called that “providential.” We don’t see the whole picture, either the whole picture of nature or the whole picture of history. Diseases, though bad in themselves, might well be part of an overall design which is “very good” – a design which only God can see.
And what is the alternative? Suppose some horrible disease arose not as part of any design on God’s part, but as an accident of evolution. Does that help theology any? Would God be off the hook, morally, for allowing evolution to produce horrible things whose existence he could have prevented? I don’t think so. I think the buck stops with God, no matter what. That is why the idea of a designed disease doesn’t trouble me as much as it troubles some others. We may not have a clear idea why a good God would design malaria; but we don’t have any clear idea why a good God would tolerate the accidental production of malaria by evolution, either. God is responsible in any case.
The YECs try to make God not responsible, by making physical evils the result of the Fall, and hence entirely man’s fault. But God surely was powerful and wise enough to create nature such that the Fall’s effects would be confined to evils that were spiritually educative for man (e.g., hard work, both to till the soil and to bear and raise children); surely he could have made Adam and Eve pay for their disobedience without allowing the Fall to produce horrible child diseases which were all out of proportion to a single act of disobedience (and without allowing the Fall to harm non-responsible bystanders to boot, e.g., sheep who would now be eaten by wolves). Because Adam and Eve ate an apple, tigers now have to eat lambs, and children have to die of scarlet fever or appendicitis? It seems absurd to blame Adam and Eve for that. God could have rigged things so that the punishment for disobedience would be severe, without being wantonly cruel or sadistic. He’s omnipotent and omniscient. So if Adam and Eve’s action produced a horrible distortion of nature and vast suffering, God is ultimately to blame for those consequences. YEC theologizing can’t get God off the hook for natural evil by the expedient of blaming man.
In the end, Christians have to take seriously their own words when they continually claim that God is omnipotent, and sovereign over all, and providential regarding all things. Whether he creates directly or sub-contracts the work to evolution, he is still the author of what happens.
Thus, in my view, YECs on the one hand, and TEs like Ken Miller on the other hand, end up covering up the depths of the problem of suffering, by offering crudely mechanical explanations for it (Adam and Eve ate an apple, so all of nature fell by some kind of automated chain reaction; God didn’t intend evil viruses and parasites, but evolution is out of his control once he ordains it, and they happen as unwanted side-effects). I think both the Bible and the Christian tradition see something more difficult, and more impenetrable in the existence of evil than many of our modern writers. And if ID leaves unanswered the question why a designer would create malaria, that’s no more surprising than the fact that Christian theologians throughout the ages haven’t provided a fully satisfactory account of why God permits physical evils. And Christians don’t stop believing in God just because they can’t explain why he lets a young child die of scarlet fever, or an lets an avalanche destroy a Welsh coal-mining town, or lets millions be slaughtered by a Hitler or a Stalin; so why should ID folks stop affirming design based on irreducible complexity, because they don’t know why the designer would make such a thing?
Jon Garvey’s new book on the Fall is very good on many of these points. I don’t claim to be speaking for him here, but I agree with him on many aspects of this matter.