I don't go for this minimality-uber-alles line at all. When a ballad describes what six of the seven brothers do before the seventh does the killing, it's performing two *non-narrative* functions: decribing some of the alternate human responses to the situation, and involving the audience in a ritual where suspense and the passage of time are essential to the effect. The first gives the singer an opportunity to portray character, the second provides one of the most easily comprehensible ways for a modern audience to experience an alternative to the hegemonic soundbite/video-game culture of the present day. If you can't enact those ritualized repetitions in a way that involves the audience, you shouldn't be doing that sort of song.

Child ballads are miniatures compared with the narratives of the Middle Ages, anyway. People's brains haven't changed over the last 1000 years, just their expectations.