'I would add that some time in the late 30s/40's the music industry misappropriated the term to refer to any slow love song they wished to perpetrate on the public.'

Are you quite sure its not the world of folk music buffs who have misappropriated a term which is in common usage? If we decided things by democratic means - you lot would have lost your deposit.

Even in the world of folk music - I have heard simple love songs like Plaisir d'Amour referred to as a ballad.

I don't know why we always seem to be engaged in this sort of discussion - folk music means this, and now a ballad means that...

And what of the murder ballads....the fatal summer school of American folksongs - they don't really all fit your blueprint. sometimes they get taken over by another school of music - like Mckinley or White House Blues. Presumably at one time a doleful tale of the assasination - but before long a happy go lucky ragtime and bluegrass favourite.

I think whatever you decide - the folk process will frustrate your plans to confine it to one meaning. If only because of the nature human creativity and ingenuity.