A very intimate vocal like you've mixed in the quiet parts requires a bit of treating to be comfortable, (particularly through headphones)...some de-essing would be the main thing.
The leap from slow & sparse to paster & full band needs, to my ears, to be either sudden and shocking or introduced smoothly.
Very interesting piece...I can hear Steeleye Span doing a fab version.


Cheers
rayc
"What's so funny about peace, love & understanding?" - N.Lowe