In reply to AlanLittle:
If you watched the video you'd see what I meant, but as a sweeping summary I was referring to rock types which require sensitivity over stiffness - not those who's feelings are easily hurt.
Clearly exceptions occur, but by and large gritstone, sandstone and granite benefit from something you can feel the rock through, as they're more friction based rock types. More edge based rock types such as rhyolite don't (necessarily) require the same level of sensitivity, as they benefit more from a stiffer shoe which will allow you to push off the most marginal footholds, which are - by their very nature - more positive (i.e. edge, not smear).
Either way, that should clarify my meaning.