Good post, John!
Just a couple of comments.
The differentiation between "hard" & "soft" pads is much less marked with modern friction materials. A lot of work has gone into, & continues, in developing pads which have acceptably high friction levels over a very wide temperature range.
Friction level is dependent on rubbing speed; again, modern pads have reduced this effect to almost insignificant levels.
Developing friction materials isn't easy - it's still as much a black art as it is a science!
Finally, the main reason for a more expensive standard pad over a cheaper one is in the single pressing manufacture rather than batch manufacture. A pad formed in an individual pressing tends to be a much more consistent pad which has less performance variation.
How so? Do you mean single-cavity versus multi-cavity dies, are we talking press-cured, open-cured or pack-cured pads? Define "performance variation" in this context.
A big advantage of mass-production methods is rigid process control which helps reduce differences in the products within a batch & from batch to batch compared with manufacturing a series of one-offs.