Insane,
As your name suggests, you are obviously on a different plane to the rest of us.

A different planet evidently, Steve. Still, I wasn't aware there was any consensus on sanity - certainly not on Mudcat anyway, where cranky idiosyncrasy seems very much to be the order of the day. Still, if you feel the need to hurl around that sort of abuse just to show how normal you think you are, then I'll take that as a fair indication of the contrary. Welcome to the club, dear boy!

As a story-teller you have a vivid imagination, and so you should, but traditional ballads tell a simple straightforward story and any powerful imagery is often an interloper inserted at some point by someone like yourself.

As a storyteller I don't have an imagination at all, vivid or otherwise; in fact, I would say that's the very thing a storyteller should not have, especially one (such as myself) who only tells and sings traditional material. Traditional ballads tell any amount of stories, in any amount of ways, but seldom are any of them so simple or indeed straightforward at any level that they would require the sort interloper you suggest.

No doubt your tales contain 'various & richly complex levels of meaning & experience that ultimately only the listener might ever become aware of, and even then not necessarily on a conscious level.'

Ultimately, the experience of any narrative (traditional or otherwise, but let's assume traditional here) is essentially subjective; the role of the singer or storyteller is mediumistic to this end - their job is not a creative or imaginative one, but simply one of a performer. Whatever empowers them in this respect, they do not determine the nature of that experience for the listener, nor yet are they themselves aware of the inherent layers that exist within any given narrative, any one of which might set off any amount of triggers within the mind of the listener. Thus do I say complex levels of meaning & experience that ultimately only the listener might ever become aware of, and even then not necessarily on a conscious level.

but the vast majority of traditional ballads do not!

Oh but they do, Steve - they all do. Apart from anything else, in balladry, imagery and narrative coexist in a poise of intimate union; they are part and parcel of the self same purpose, the one thing carrying the other in perfect accord. The experience is, therefore, at that point whereby the subjective mind is inseminated by the objective image, a process which isn't just limited to the experience of traditional ballads, but all levels of narrative (which might include a play by Edward Albee or a mother-in-law joke by Bernard Manning). The ballad imagery, as with traditional folk songs & stories, is borne from a collective process, and shaped, accordingly, to the requirements of such material in terms of pure function - which is to say, there is a very definite reason for each and every one of them, no matter how essentially unsayable that reason might be.   

The Duke's daughter in 'The Cruel Mother' meets up with the ghosts of her 2 murdered infants and without any surprise or narrator's comments she accepts their condemning of her to hell in compliance with contemporary beliefs.

Well, there's any amount of versions of The Cruel Mother - so perhaps a comparative study is in order here? In the version I'm most familiar with, she doesn't accept her punishment at all Welcome, welcome, bird on the tree / Welcome, welcome, fish i the sea / Welcome, welcome, eel i the pule / But oh for gudesake, keep me frae hell! - which is, in any case, as rich a piece of imagery as you'll find. An interloper? I hardly think so. In fact if anything's an interloper with respect to The Cruel Mother it is the conception set up which does feel extraneous to the sense of the song - only 5 of the 13 featured in Child feature this scenario, and maybe the same is true of versions elsewhere. Otherwise, I'd say the whole ballad operates on a level of pure imagery, all the more apparent in the version one may hear superlatively sung by Mrs Pearl Brewer of Pocahantas at The Max Hunter Folk Song Collection - this is reduction to the pure essence of the thing which even on a conscious level carries a richness of imagery as to be quite breathtaking.