Peter, re: Edwards, I've read differing accounts of his preaching mannerisms. But this much is consistent in the accounts: he wrote either an extensive outline or a complete manuscript.
Re: a sermon review center, I'm sure that it would prove helpful at points. There is wisdom in a multitude of counselors. I've seen a number of articles over the last 5-6 years encouraging ministers to write their sermons in conjunction with church leadership; some seemed to have the congregation's best interest in mind, and assumed that more minds would equal better illustrations/applications/expositional clarity. Others basically presented it as a way to knock out the sermon and get on to the "more important matters" of ministry.
I read recently that one of the big-name Reformed guys (I think it was Mark Dever, but I might be remembering incorrectly) writes his sermon ms, and then reads it one paragraph at a time to a group of elders at his church on Saturday. They make suggestions as to clarity, transitions, etc., and he edits appropriately. So you're not alone in your thinking.