In an article entitled "Plexiglas Preaching", John MacArthur describes what he believes is the problem of superificial preaching that is as "lightweight as the plexiglas lecterns from which these messages are delivered." I think a few excerpts are enlightening.
"There are plenty of gifted communicators in the modern evangelical movement, but today’s sermons tend to be short, shallow, topical homilies that massage people’s egos and focus on fairly insipid subjects like human relationships, 'successful' living, emotional issues, and other practical but worldly—and not definitively biblical—themes...
"...listing the negative effects of the superficial brand of preaching that is so rife in modern evangelicalism.
"It usurps the authority of God over the soul. Whether a preacher boldly proclaims the Word of God or not is ultimately a question of authority. Who has the right to speak to the church? The preacher or God? Whenever anything is substituted for the preaching of the Word, God’s authority is usurped. What a prideful thing to do! In fact, it is hard to conceive of anything more insolent that could be done by a man who is called by God to preach."
From Plexiglas Preaching, by John MacArthur