When you walk into a church you are not familiar with (maybe you are visiting the area, maybe you don't usually attend church) what you get is a book or a sheet with the words, or even see the words on an overhead projector screen. Very few hymn books these days have a melody line edition, and if they do the churches can't afford them. And when you have a projector you never get the music. And maybe you don't read the music anyway. And you don't know the hymn. Can you join in? Thats what I think that people who choose hymns should think about, can somebody who doesn't know the hymn and doesn't have the music pick it up and sing it. Too many modern songs have an unpredictable tempo which make this impossible. Some are OK, most of Graham Kendrick's for example, because I think he understands the structure of a hymn. But too many are completely impossible.