Admitting to God "I want X, not Y, though I know you want me to want Y" is perfectly fine. If it is in fact true, why not put it before God? It should definitely be accompanied by a petition to be given the grace to want Y. But as Herbert McCabe argues, the very act of putting these desires in prayer begins the process of recognising that we don't really want X.
But there's a difference between admitting in prayer that you want X and praying for X.
If one is not sure whether X is good or bad, but one wants X, then one may pray for X. The point of that is just our recognition of God's Fatherhood. Children ask their parents for what they want; they are not bothered about making requests of them. Jesus shows us the perfection of this sort of petitionary prayer: adding, "Yet not my will, but your will, be done."
But if one knows or thinks that X is bad, yet one still wants X, then one should not pray for X. It is good to recognize that one wants X, and even to mention that in conversation with God, but that isn't petitionary prayer.
Augustine's "Lord, grant me chastity and continence, but not yet" is surely not the perfection of prayer, taken literally. It might be taken non-literally, as an ironic acknowledgment of one's weakness. But literally to pray for what one knows God does not want shows disordered attachment to things and division in one's members.