Interesting post - you do highlight what seems to be a racing heritage in bikepacking.
Shakedry - i have an older gore which i rate and is pretty compact (for me) - i did once pic up a shakedry in a shop and was impressed by the materials tech - aren't they perhaps a bit delicate for touring though? am thinking in particular that if freecamping you might be brushing past the odd tree etc.
I personally tend towards the more heavyyweight maybe more durable stuff - in fact haven't used my Gore in a fair while - my favourite waterproof jacket for touring and general purpose use is a thing i picked up in aldi for £20, should have grabbed another for a tenner when I had the chance,.