From what I understand, the criticism of the Catholic (Thomistic) doctrine of created grace is that it cedes too much to the nature and power of man in the process of sanctification. It also tends to reduce the role of the Holy Spirit once the habits of virtue/charity have been created. The Easterners are especially not happy about the second point, whereas us Protestants are especially not happy about the first point. I’m far from being an expert on the topic, so I’m far from any willingness to pronounce a firm judgment, one way or the other. I do like Henri de Lubac’s presentation of the doctrine, which surely mitigates some of the problems or at least points in that direction. The following is from A Brief Catechesis on Nature and Grace (Ignatius Press, 1984):
The supernatural, one might say, is that divine element which man’s effort cannot reach (no self-divinization!) but which unites itself to man, “elevating” him as our classical theology used to put it, and as Vatican II still says (Lumen Gentium, 2), penetrating him in order to divinize him, and thus becoming as it were an attribute of the “new man” described by St. Paul. While it remains forever “un-naturalizable,” it profoundly penetrates the depths of man’s being. In short, it is what the old Scholastics and especially St. Thomas Aquinas called (using a word borrowed from Aristotle which has often been completely misunderstood) an accident, or call it a habitus, or “created grace”: these are all different ways of saying (even if one thinks they need various correctives or precisions) that man becomes in truth a sharer in the divine nature (divinae consortes naturae; 2 Pet 1:4). We do not need to conceive of it as a sort of entity separated from its Source, something like cooled lava — which man would appropriate to himself. On the contrary, we wish to affirm by these words that the influx of God’s Spirit does not remain external to man; that without any commingling of natures it really leaves its mark on our nature and becomes in us a principle of life. This Scholastic notion of created grace, so often belittled today, does express the incontrovertible fact that “it is we, ourselves, and our creaturely being, which the active presence in us of the Spirit makes divine, without for that reason absorbing us and annihilating us in God” (Louis Bouyer, Le Père invisible, Paris: 1976, 288).
For St. Thomas, as Fr. Louis Bouyer explains,
the soul…will find its completeness and go beyond itself in God. Disagreeing with Peter Lombard, in fact, he would not admit that grace is purely and simply the gift of the Holy Spirit, of the Third Person of the Trinity as it is in itself…. He realized that if such were indeed the case, man would certainly be the temple of the Spirit, but not God’s living temple, vivified by the presence of its Guest who assimilates our life to his divine life. The uncreated grace of the gift of the Spirit, according to him, has its prolongation in the soul itself in created grace, i.e., a divine quality that assimilates the soul to God and makes it share in his own life. (Introduction à la vie spirituelle, Paris: Desclée, 1960, 154-55)
Grace is supernatural in the fundamental sense that it is superior to any created or creatable nature, but it is in no sense a “supernature.” It is, so to speak, a new “accident,” “hidden in and penetrating the substance of the soul and rendering it, as a soul, capable of living God’s own life, his divine life” (Ibid).
[A Brief Catechesis on Nature and Grace, pp. 41-42, 45-46]