im not sure how many people already know about this/have done this but...
i would certainly recommend changing HKLM\DRIVERS\TOUCHPANEL "PRESSURETHRESHOLD" from w/e it is to the highest value (FFFFFFFF in hex).
it makes a difference. not too much, because in the end the software can only do so much, and it was dumb htc making the screen so unresponsive (my dads axim x30's screen is *F A R* more responsive...).
but i do know that it makes a difference, because i once input "2" because i wasnt sure it was doing anything and... ended up having to hard reset my phone because the screen wouldnt do anything no matter what...dont put it too low!
The pressure sensitivity settings are overridden anytime you do a screen calibration. As a matter of fact, the lighter you press on the screen calibration screen, the higher the sensitivity numbers are set.