JI Packer is a pastor, author and one of the most influential Evangelical thinkers in America. Here was his response to a question asked by Shane Rosenthal regarding niche marketing in the church. I think good arguments could be made on all sides, but did find his response insightful.
Shane Rosenthal: What do you think about a niche marketing approach that has by virtue of the different worship styles--teen pop, alternative, and adult boomer--created generational segregation?
J. I. Packer: We have separated the ages, very much to the loss of each age. In the New Testament, the Christian church is an all-age community, and in real life the experience of the family to look no further should convince us that the interaction of the ages is enriching. The principle is that generations should be mixed up in the church for the glory of God. That doesn't mean we shouldn't disciple groups of people of the same age or the same sex separately from time to time. That's a good thing to do. But for the most part, the right thing is the mixed community in which everybody is making the effort to understand and empathize with all the other people in the other age groups. Make the effort is the key phrase here. Older people tend not to make the effort to understand younger people, and younger people are actually encouraged not to make the effort to understand older people. That's a loss of a crucial Christian value in my judgment. If worship styles are so fixed that what's being offered fits the expectations, the hopes, even the prejudices, of any one of these groups as opposed to the others, I don't believe the worship style glorifies God, and some change, some reformation, some adjustment, and some enlargement of spiritual vision is really called for.
From: "An Interview with J. I. Packer: The State of Evangelicalism" (July/August 2008, pp. 40-42). (Unfortunately, online access to the complete article requires a subscription.)