Preaching as confessional?

On the note of preaching this morning (see below entry), I was reading a book about preaching recently where the author made a comment that interested me in a list of 'do nots' for preachers. The author said that preachers should not use the pulpit as a confessional - that his confessional is done in private between him and God. I'd be interested in quizzing him further about what exactly he meant by this. I agree that it is right for a preacher to be wise and careful about what they say - and especially if they are in a leadership role of some kind in the situation in which they are preaching. I wouldn't want a preacher to spend a whole sermon sharing their own faults or dark secrets or whatever. A sermon shouldn't be self-centred. But at the same time I'm not convinced that there is anything wrong with a preacher admitting that what they are preaching about is difficult to accept / understand sometimes and that they themselves often find whatever it is hard; to admit that they do often find it a struggle to practice what they preach. I think that it is often easier for people to relate to, and accept what they hear from, preachers who can be honest about their own struggles and difficulties - their need for God and the strength of His Holy Spirit. Like I say I know that a preacher should be wise about this, and the appropriateness of saying certain things has to be judged according to each context / situation - but surely not to the point of not being real at all and running the risk as coming over to people as aloof??