If Google Docs can help me loose weight, why not Wikipedia for preaching? (Not that I'm preaching much these days.)
Not for fact-checking (though I find a well-cited article is helpful for follow-up reading) but for style. Wikipedia has a house style that helps improve reading and factual quality while smoothing out writer idiosyncrasies. While I would hate all preaching to sound alike -- and that's the limit of a common style -- there are enough preachers out there (novices, the rusty, the undisciplined, the harried) who could benefit from dispassionate rules and I know there are a few congregations that would approve!
A good number Unitarian Universalist preachers I've known have a special set of bad habits, including making broad, unsupported claims. (A breathy, faux-spiritual delivery is another: good style can't help everything.) Reading and abiding Wikipedia's counsel against peacock terms and weasel words could well right help.
The full list of style articles (Wikipedia)