One interesting point that one finds in Duffy (though I don't think it is his intention to highlight this) is that worship in the pre-Reformation English Church was pretty much entertainment. Sound familiar? Now it's a different sort of entertainment, but it's still that. The English Church in particular went to great lengths to engage in what might be called pageantry. For example, on Candlemas, they would literally have people dress up like Mary and Joseph and present the infant Jesus to people dressed like Anna and Simeon in the church service. On Good Friday, they would consecrate a host, put it in a special monstrance, and then bury it until Easter morning in a special crypt they built in the Church. In other words, Jesus would literally rise from a tomb all over again!
This brings up an important point about our present situation. When worship is entertainment or pageantry, it's bad- whether it's liturgical or not. Traditional Lutheran liturgical worship is good because it centers on Word and sacrament. But if it's not doing that, it's just as bad as Contemporary pop-rock worship.
Now some people might find this a puzzling point to make in our context, but I don't think it is. I won't name any names, but there are definitely pastors in the LCMS who hold that certain liturgical forms are simply good for their sake. They go on and on about the history of the liturgical form, and don't talk too much about whether or not the form promotes Word and sacrament.
One LCMS theologian (who will not be named) wrote a book where he discusses how Christian worship when properly understood is a liturgical "script" meant to reenact the events of holy week. Thinking like this is as problematic as Church-Growth talk. Both assume that the worship's purpose is to do something to make the Word work. Language of "reenactment" presupposes a theology of an absent Christ. If Christ isn't present in the Word, converting and justifying sinners, then we need to stand in for him and do his work for him through our worship.
This approach is obvious attempted by the Church-Growth movement with it's boyfriend Jesus songs. But it is oddly enough also the approach of those hyper-liturgical folks in the late Middle Ages and some people in LCMS. From this perspective, since Jesus is absent in the historical past, liturgy must serve the function of reenacting the events so as to make them present. In this, the power of the Word is denigrated. Ultimately, this approach to Christian worship works from the same faulty assumptions as Church-Growth and should be resisted.