Watching EC and the Ratccatchers on youtube, I think that singing a song like The Good Old Way in one's sweet/sunday best voice would rob it of it's urgency and driving force.

Here is an interesting article on 'regulationism', from one of your favourite sources.
http://en.wikipedia.org/wiki/Regulative_principle_of_worship
You wouldn't be singing anything from Hymns Ancient and Modern if they had their way!