"Jim's point, though, is that ornamentation and storytelling don't go together, since one is likely to distract attention from the other."
That's not what I said Brian - ornamentation for ornamentation's sake can do just that, but used subtly to underline important words, it can be an invaluable addition to the song
Joe Heaney was interviewed over quite a long period by Ewan and Peggy and he spoke at length about the uses of ornamentation
The same with accompaniment, though I have never been convinced that the Guitar is the best instrument
In both cases it's the "look how clever I am" approach to the song that spoils the song for me - neither songing nor instrumental playing

I have always though 'Little' Bill's singing to be superb, but I find, for various reasons, it doesn't have the emotional mileage for my taste - once you've heard it a few times, you've heard it
Sam Larner's unornamented singing, particularly 'Butter and Cheese and All' always leaves me feeling it's the first time I'm hearing it - and it's the first time Sam had sung it
I don't know if that makes sense!

"Surely the altering and changing of a song is part of the folk process is it not? "
Nope - every song that had ever been changed wulfd be a folk song using that logic
Jim