There is no logical contradiction entailed by God's creating only persons who are both essentially free and are saints (i.e. persons with “the property of being such that there are some occasions on which one has a capacity for wrongdoing and no occasions on which one in fact does wrong.”1This is relevant because...
Antony Flew: “If there is no contradiction here then Omnipotence might have made a world inhabited by perfectly virtuous people.”2
But so what if there is no contradiction? Something can be metaphysically impossible and/or not feasible for God while simultaneously not entailing a contradiction.3
John Mackie: “If God has made men such that in their free choices they sometimes prefer what is good and sometimes what is evil, why could he not have made men such that they always freely choose the good? If there is no logical impossibility in a man's choosing the good on one, or on several occasions, there cannot be a logical impossibility in his freely choosing the good on every occasion. God was not, then, faced with a choice between making innocent automata and making beings who, in acting freely, would sometimes go wrong: there was open to him the obviously better possibility of making beings who would act freely but always go right. Clearly, his failure to avail himself of this possibility is inconsistent with his being both omnipotent and perfectly good.” [“Evil and Omnipotence.” Mind 64: 200-212.]