I have a friend who is writing a research paper about prayers of lament. She is arguing that the lament is a valid, important, missing element in American worship. I agree with her premise overall. From what I’m seeing, the majority of large, urban churches in America that are aggressive towards church growth include joyful praise, pop/rock style, upbeat songs (at least to begin the service), and a lack of somber lament and confession.
American music has been greatly influenced by Europe, Africa and other cultures in the last several hundred years. Joy and praise in worship are not just an American phenomenon. Latino and African culture tend to be quite joyful, passionate and expressive. Asian cultures can often be more reserved and contemplative. There is something to be appreciated in every culture. Each changing generation both gains and loses something.
I’m not that concerned with changes in music style which are to be expected over time, but I am burdened for the lack of prayer and the content of our liturgy and songs. Corporate prayer, laments, and confession of sin seem to be missing aspects of American church worship. My dad travelled to American evangelical churches extensively over the last 5-6 years, and he rarely heard churches pray; he mainly heard songs and sermons. Church worship gatherings should include more than just sermons and songs of praise. There needs to be an emphasis on the ordinances and sacred actions of the New Testament.
The Lord’s Table (communion) in American churches tends to have a somber, serious tone (which is not true of all cultures) and confession of sin. During my time in Africa, communion was experienced as a joyful celebration of the resurrection. So, this aspect of somber confession is often expressed in the American church during communion (about once a month in my circles).
I would encourage the wisdom of incorporating more prayer, laments and confession of sin in corporate worship. It is appropriate to come to God in prayer as we are . . . honest and broken. Early church liturgies included lengthy confession of sin. There is much to be learned from their practice and example. You can explore some early church liturgies at: https://joshberrus.wordpress.com/2007/04/24/early-liturgies/.
All Biblical elements in worship are crucial and important. The early church in Acts 2 was devoted to the apostles’ teaching, prayer, fellowship, breaking of bread, and all Biblical ordinances and practices in corporate worship. Believers should respond with sacrificial devotion in all the Biblical elements. Christians are to worship God with passion and zeal through Scripture reading, prayer, confession, giving, communion, baptism, testimony, music, preaching, serving, and all Biblical practices for the aim of the glory of God.
Here are some suggestions for worship planning:
https://joshberrus.wordpress.com/2008/11/21/worship-planning/
Josh's Blog 
I am deeply involved in an American church in Florida. There certainly is a move away from the somber, sort of, sin-consciousness in the worship services. The sense is that it is more honoring to the finished work of Jesus Christ and more appropriate for us to focus on our new position of having our conscience purged from dead work to serve the living God (Heb.9:14;
10:2) more than to focus on our sin which cost Him HIs life. Not completely sure that focusing on sin causes us to have victory over it. Apostle Paul in 1 Corinthians 6:14 mentioned that sin won’t have dominion over us, not because we focus on it, but because we focus on being under grace. Thanks.
I attended Mass at an Eastern Rite Catholic church recently. The reverence and sanctity of the Mass and quiet presence of the divine were palpable. I agree with your comments.