Does not fly. You assume that God is bound by the existing natural laws. Granted; I do not expect God to rule the world by a miraculous fiat (on the other hand - why not, since he is omnipotent and supremely good?) In which case he should have created world with a more benign physics. I do not know how - I am not all-knowing, he is. The thesis that this is the best world of all possible ones assumes that god is somehow limited in his possibilities. If this is all he is capable of, he should have abstained.