From James Hastings Nichols, Corporate Worship in the Reformed Tradition, p. 109.

…in most cases the legatees of the Westminster Assembly Puritans did not care to maintain the full prescriptions of the Directory.  The anti-liturgical current moved most of them still farther to the left.  Perhaps the most faithful exponents of the Directory after the Restoration were the Episcopalian minority in Scotland, who were distinguished, not by the Anglican prayer book, which they did not follow, but by their use of the Lord’s Prayer, the Creed, and the “Glory be to the Father” in a service modeled on the Westminster Directory.  The Church of Scotland itself had by the end of the century come close to the position maintained by the Congregationalists against the Presbyterians at the Westminster Assembly.  Presbyterians generally gave up the liturgical use of the Lord’s Prayer, despite the recommendations of the Directory, and adopted the Congregationalist fear of the uncommented reading of Scripture.  And eighteenth-century Scottish Presbyteians could get into trouble for following the instructions in the Directory as to reading Scripture and using the Lord’s Prayer.  Even metrical psalmody suffered.  The custom of “lining out,” conceded by the Directory in cases “where many in the congregation cannot read,” became the normal practice in Scotland and America in Presbyterian and Congregational churches.