You've mentioned hymns that parallel sermons. In several ways. One is the sustained Bible reading, and going through the lectionary, that one does in order to write and preach a sermon each week. The Bible stories soak in. Another is, trying to avoid platitude and cliche in what I write.
Church members deserve more.
I think I try to make my writing honest. We can sing out beyond ourselves, we can sing a faith we don't completely feel on a given day, but the words for that should have integrity. They should be grounded in the Bible, for example. That sounds very serious. For example, I've written a series of hymns based on Medieval Epiphany legends.