Read and React: WELS FAQ on Contemporary Worship

Contemporary worship – WEL FAQ

The following quotes are the content of the above linked WELS FAQ entitled "What is the WELS view on contemporary worship styles?" followed by my commentary.
We recognize that God has not prescribed how we are to worship him. (sic)
This is an interesting claim. It is true in the sense that God was very particular in the prescribing the worship of the Old Testament. Meticulous, even! But we don't have a New Testament book that mirrors say Leviticus. But we are not Marcionites, so we can draw insights from Old Testament worship to guide our own. And the New Testament describes what worship consists of: Continuing steadfastly in the Apostles' doctrine and fellowship, in the breaking of the bread, and in prayers (Acts 2)

The choice of the word "prescribed" is an interesting one since the prescriptive/descriptive dichotomy is often used against the Book of Concord: namely, that Article XXIV of the Augsburg confession, where we state that we retain the mass and celebrate the Lords Supper every Sunday, are 'descriptive' of the Reformation era worship and not prescriptive of our worship today. The proper response to such arguments is that it describes the practice of confessional Lutherans (let the reader understand). 
Because of that, we enjoy Christian freedom in our corporate worship life. Decisions about worship styles are made at the congregational level.
Stylistically there can be variation, but if we recall that 'synod' means 'walking together' ... those stylistic choices should be minimal to reflect the broader group of saints we bind ourselves with. 

Content-wise, we retain the mass. If you are missing elements of the mass - particularly the major elements like the readings, sermon, creed, and supper - your worship fails to meet the description of Lutheran.
What guides congregations in their worship life is a desire to glorify God (1 Corinthians 10:31), to do things in an orderly way (1 Corinthians 14:40) and to give God our best (Isaiah 1; Malachi 1). 
This sentence is the crux of the matter and why it is difficult to have intelligent conversations with contemporary worship advocates. Remove the adjectives and adverbs and the simple sentences read:
congregations glorify God

congregations do things

congregations give to God

To the contemporary worship proponent, worship is what I do to God. Contemporary worship is by nature solipsistic.

To the liturgical worship proponent, worship is a poor choice of word and what we do on a Sunday morning should really be called Divine Service, because it's primarily about what God does to me and then my thanks and praise for His good gifts. 

This is the crux of the issue and why we can't have nice things.
Recognizing the diversity of the body of Christ (Revelation 7:9) will also lead congregations to conduct worship services in ways that reflect the culture(s) of their members.
This is an interesting proof-text for diversity in style. John sees a great multitude (indeed, it is the entire church) of ever nation and tribe and people and tongue standing before the throne and the Lamb. They are all wearing the same white robe (the righteousness of Christ). They are all holding the palm branch in their hand. They all cry out with the same great voice - the same pattern of words! The same style! So while there is a diversity in humanity, there is unity in worship. Quite the opposite of what the anonymous Q&A author intended. 
Regardless of worship styles, our worship is and needs to remain focused on Jesus Christ, the Son of God, our Savior. Our worship is and needs to remain focused on the Triune God. Our worship is and needs to remain focused on the precious gospel of our Lord. When that focus is maintained, then the “how” of worship can be kept in proper perspective.
Again, the "focus" starts with me. If worship is focused on Christ, it's me doing the focusing. If worship is focused on the Triune God, it's me doing the focusing. If worship is focused on the Gospel, it's me doing the focusing. Grammar betrays the fallacy.

Those things are necessary, but not sufficient. We retain the mass, or we are not Lutheran.