Even Psalms that don’t register on the list of imprecatory ones can be a challenge to use if only because of their depiction of the death of God’s enemies. Some advise against their use and this was one of the reasons for not producing, as the OPC and URC did, a complete Psalter:
The psalmist was praying against those who persecuted him. The theocracy, God’s reign in Israel from the time of Moses to the time of Christ, was a shadow of future events (Heb. 10:1). One of those events is the final judgment of God. The destruction of the Canaanites in the days of Joshua was a shadow of the final judgment and not, therefore, normative for how we are to deal with our neighbors who do not believe in Jesus. The imprecations against the wicked in the book of Psalms were also shadows of the final judgment—appropriate for the era of the theocracy, but not for this present age. The gospel era is one of kindness, tolerance, and patience—intended to bring people to repentance and faith (Rom. 2:4). This is the day of salvation (2 Cor. 6:2). And this is why Jesus taught us to love our enemies and to pray for them, not against them. This is why Paul taught us to pray that God would bless our enemies (Rom. 12:14; 1 Cor. 4:12). Like the psalmist we leave vengeance to God, but unlike the psalmist we pray that God would bless those who bring pain into our lives. (Cornerstone Biblical Commentary, Psalms and Proverbs, pp. 348–49)
Others, though, notice that Christians still pray for God’s judgment upon his enemies even in the New Testament:
We need to be very conscious of trying—that part of what we’re called to be as the light of the world is people who love our enemies. Paul talks about how loving your enemies will further increase their punishment. So setting love of enemy radically over against judgment is not biblical.
I think it is not illegitimate to use the imprecations of the psalter to pray for judgment on God’s enemies. Every time we pray, “Come quickly Lord Jesus,” we’re praying an imprecation on God’s enemies. When Jesus comes again, there will be judgment for God’s enemies.
In other words, when Jesus taught his disciples to pray, he included the petition, “Thy kingdom come,” which as the Larger Catechism explains involves praying for the “hastening” of the kingdom of glory:
that Christ would rule in our hearts here, and hasten the time of his second coming, and our reigning with him forever
Not to be missed is the nature of the office that Christ executes as king:
Christ executeth the office of a king, in calling out of the world a people to himself, … restraining and overcoming all their enemies, and powerfully ordering all things for his own glory, and their good; and also in taking vengeance on the rest, who know not God, and obey not the gospel.
In which case, the anti-imprecatory Psalm position implies editing the Lord’s Prayer.
That does not mean that prayers for judgment day are easy to pray. The image of that great separation of the saved and the lost is haunting. At the same time, the thought of the end of the world is never absent from Christian devotion and worship.
On the upside, at least Protestants debate something that Roman Catholics don’t anymore thanks to an effort to manage less than good acts and desires with procedural standards and practices.