Tom,
Thanks for your thoughtful posting; plenty to think about - will go off and think.
In the meantime, MacColl argued that the only way to get an audience to feel the song was for the singers to feel it themselves. This appeared to be part of the traditional singers art, but not that of the revival. Unfortunately, we do not have enough evidence to say this for certain, only bits and pieces from singers like Walter Pardon, Tom Lenihan, Texas Gladden etc. I believe Ken Goldstein did some detailed work with New York State singer, Sarah Cleveland along these lines, but have never come across his conclusions.
Walter Pardon gave us a great deal of information on how he saw his songs, and how he detached himself from his audience while singing.
As an actor/producer/playwrite, MacColl was of the Stanislavski school and used such devices as 'emotion memory' and 'application of the idea of "if"'. He transferred some of that work to his singing. I have seen (and experienced) some of that technique in action with spectacular results, not in actual performance, but in preparation. The idea was that once you had established an 'in' to the song it was there permanently to be drawn upon. His recommended reading was Stanislavski's 'An Actor Prepares'.
It strikes me that nowadays the balance has shifted away from content to form; a friend put it nicely last weekend at the Frank Harte week-end when she said, "singing has become more about the singer than the song".
Jim Carroll