On Separation: it is interesting that those who don't believe in "secondary separation" (separation from disobedient brothers) accuse those who do of being divisive. Ironic, isn't it? If the goal is unity of the church at large, shouldn't you refrain from harming the unity of the body by calling people who differ from you divisive, especially when you complain about them doing that?
On preaching: the problem with some preachers is that they are more in love with their message than they are with their people. What I mean is this: For some preachers, the pursuit of the perfect homiletical outline has overridden their obligation to think about the audience to whom they are preaching. While the message should never compromise because of an audience, it should also never fail to communicate with the audience. The preacher must begin his preparation with two eyes on the text. He must finish his preparation with one eye on the text and one eye on his audience. One pastor I read talked of doing his final sermon prep at the food court in a local mall. He would see the people walking about and think about how his sermon would plug into their lives. It's not a bad suggestion.
On slogans: slogans are great tools. They are generally bad solutions. They are, by nature, usually memorable, but simple. I love those who can take a complex truth and boil it down to a simple memorable statement. But we must be cautious about naked sloganeering. Most of them need the clothing of explanation and application. For instance, I frequently give the whole message of the Bible in two words: God wins. It's a slogan. It's true. It also needs explanation. God's victory includes a lot of things along the way that need to be explained, defended, applied, and accepted. So by all means, use slogans when you can, but use them carefully.
Finally, on analysis: if you are going to do an expose of something, make sure you do your homework. Case in point: John MacArthur has recently written a book about the emerging church movement. It is being roundly criticized by some who believe that MacArthur did not do enough homework in preparation for the book. Though I have it, I have not yet read it (not sure if I will anytime soon). Questions are being raised: How many emergent church services did MacArthur attend? How many interviews with emergent church pastors did he conduct? If the answer is none, that is bad. When the people you are writing about do not recognize themselves in your writing, there may be a problem. Now I recognize that people being critiqued are not always objective about their problems, but they should at least recognize some of what you are saying. MacArthur's book is probably not entirely wrong, but it deserves some caution. I recommend reading both sides of the issue before you make dogmatic statements. It may save you from being wrong.
I think the emergent conversation has some severe problems. I think much of it is a distortion of historic Christianity. But I think we can show that from what they believe and do. We do not have to make stuff up, or paint the worst possible picture of a situation. Their own actions are sufficient.